v3.21.2
Derivatives and Hedging Activities - Fair Value, Derivatives, Measurement Inputs, Disclosure (Detail)
$ in Millions
Jun. 30, 2021
USD ($)
$ / bbl
MMBTU
Mar. 31, 2021
USD ($)
Dec. 31, 2020
USD ($)
MMBTU
$ / bbl
Jun. 30, 2020
USD ($)
Mar. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Fair Value Measurement Inputs Disclosure [Line Items]            
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Derivative Contracts Net Value, Ending Balance | $ | $ $ 567 $ 645 $ 1,175 $ 3,060 $ 1,660 $ 25
Interest Rate Contract [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Derivative Contracts Net Value, Ending Balance | $ | $ $ 308 319 $ 267 311 266 89
Interest Rate Contract [Member] | Level 3 [Member] | Measurement Input, Average Correlation [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.62   0.56      
Interest Rate Contract [Member] | Level 3 [Member] | Measurement Input, Median Correlation [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.60   0.60      
Interest Rate Contract [Member] | Level 3 [Member] | Measurement Input, Average Volatility [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.64   0.65      
Interest Rate Contract [Member] | Level 3 [Member] | Measurement Input, Median Volatility [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.54   0.53      
Credit Risk Contract [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Derivative Contracts Net Value, Ending Balance | $ | $ $ 1,750 1,875 $ 1,778 2,327 2,518 1,877
Credit Risk Contract [Member] | Level 3 [Member] | Measurement Input, Average Credit Spread [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 1   1.09      
Credit Risk Contract [Member] | Level 3 [Member] | Measurement Input, Median Credit Spread [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.78   0.74      
Credit Risk Contract [Member] | Level 3 [Member] | Measurement Input, , Average Upfront Credit Points [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.44   0.40      
Credit Risk Contract [Member] | Level 3 [Member] | Measurement Input, , Median Upfront Credit Points [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.30   0.30      
Credit Risk Contract [Member] | Level 3 [Member] | Measurement Input, Average Recovery Rate [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.53   0.46      
Credit Risk Contract [Member] | Level 3 [Member] | Measurement Input, Median Recovery Rate [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.40   0.40      
Foreign Exchange Contract [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Derivative Contracts Net Value, Ending Balance | $ | $ $ (234) (289) $ (338) (94) 61 (211)
Foreign Exchange Contract [Member] | Level 3 [Member] | Measurement Input, Average Correlation [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.39   0.39      
Foreign Exchange Contract [Member] | Level 3 [Member] | Measurement Input, Median Correlation [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.41   0.41      
Foreign Exchange Contract [Member] | Level 3 [Member] | Measurement Input, Average Volatility [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.18   0.18      
Foreign Exchange Contract [Member] | Level 3 [Member] | Measurement Input, Median Volatility [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.18   0.18      
Commodity Contract [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Derivative Contracts Net Value, Ending Balance | $ | $ $ 266 212 $ 300 331 388 247
Commodity Contract [Member] | Level 3 [Member] | Measurement Input, Average Volatility [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.32   0.32      
Commodity Contract [Member] | Level 3 [Member] | Measurement Input, Median Volatility [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.31   0.30      
Commodity Contract [Member] | Electricity [Member] | Level 3 [Member] | Measurement Input, Average Spread [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 33.55          
Commodity Contract [Member] | Electricity [Member] | Level 3 [Member] | Measurement Input, Median Spread [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 33.16          
Commodity Contract [Member] | Natural Gas [Member] | Level 3 [Member] | Measurement Input, Average Spread [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs | MMBTU (0.12)   (0.13)      
Commodity Contract [Member] | Natural Gas [Member] | Level 3 [Member] | Measurement Input, Median Spread [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs | MMBTU (0.07)   (0.09)      
Commodity Contract [Member] | Oil [Member] | Level 3 [Member] | Measurement Input, Average Spread [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 9.55   9.73      
Commodity Contract [Member] | Oil [Member] | Level 3 [Member] | Measurement Input, Median Spread [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 9.13   9.55      
Equity Contract [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Derivative Contracts Net Value, Ending Balance | $ | $ $ (1,523) $ (1,472) $ (832) $ 185 $ (1,573) $ (1,977)
Equity Contract [Member] | Level 3 [Member] | Measurement Input, Average Correlation [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.54   0.52      
Equity Contract [Member] | Level 3 [Member] | Measurement Input, Median Correlation [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.58   0.55      
Equity Contract [Member] | Level 3 [Member] | Measurement Input, Average Volatility [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.18   0.14      
Equity Contract [Member] | Level 3 [Member] | Measurement Input, Median Volatility [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.16   0.07      
Minimum [Member] | Interest Rate Contract [Member] | Level 3 [Member] | Measurement Input, Correlation [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.22   (0.08)      
Minimum [Member] | Interest Rate Contract [Member] | Level 3 [Member] | Measurement Input, Price Volatility [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.31   0.31      
Minimum [Member] | Credit Risk Contract [Member] | Level 3 [Member] | Measurement Input, Credit Spread [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.02   0.02      
Minimum [Member] | Credit Risk Contract [Member] | Level 3 [Member] | Measurement Input, Upfront Credit Points [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.06   0.07      
Minimum [Member] | Credit Risk Contract [Member] | Level 3 [Member] | Measurement Input, Recovery Rate [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.20   0.25      
Minimum [Member] | Foreign Exchange Contract [Member] | Level 3 [Member] | Measurement Input, Correlation [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.20   0.20      
Minimum [Member] | Foreign Exchange Contract [Member] | Level 3 [Member] | Measurement Input, Price Volatility [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.18   0.18      
Minimum [Member] | Commodity Contract [Member] | Level 3 [Member] | Measurement Input, Price Volatility [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.15   0.15      
Minimum [Member] | Commodity Contract [Member] | Electricity [Member] | Level 3 [Member] | Measurement Input, Spread [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 15.37          
Minimum [Member] | Commodity Contract [Member] | Natural Gas [Member] | Level 3 [Member] | Measurement Input, Spread [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs | MMBTU (1.59)   (1.00)      
Minimum [Member] | Commodity Contract [Member] | Oil [Member] | Level 3 [Member] | Measurement Input, Spread [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 7.62   8.30      
Minimum [Member] | Equity Contract [Member] | Level 3 [Member] | Measurement Input, Correlation [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs (0.70)   (0.70)      
Minimum [Member] | Equity Contract [Member] | Level 3 [Member] | Measurement Input, Price Volatility [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.03   0.03      
Maximum [Member] | Interest Rate Contract [Member] | Level 3 [Member] | Measurement Input, Correlation [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.81   0.81      
Maximum [Member] | Interest Rate Contract [Member] | Level 3 [Member] | Measurement Input, Price Volatility [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 1.50   1.50      
Maximum [Member] | Credit Risk Contract [Member] | Level 3 [Member] | Measurement Input, Credit Spread [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 5.68   6.99      
Maximum [Member] | Credit Risk Contract [Member] | Level 3 [Member] | Measurement Input, Upfront Credit Points [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 1   0.90      
Maximum [Member] | Credit Risk Contract [Member] | Level 3 [Member] | Measurement Input, Recovery Rate [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.90   0.90      
Maximum [Member] | Foreign Exchange Contract [Member] | Level 3 [Member] | Measurement Input, Correlation [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.70   0.70      
Maximum [Member] | Foreign Exchange Contract [Member] | Level 3 [Member] | Measurement Input, Price Volatility [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.19   0.18      
Maximum [Member] | Commodity Contract [Member] | Level 3 [Member] | Measurement Input, Price Volatility [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 0.75   0.87      
Maximum [Member] | Commodity Contract [Member] | Electricity [Member] | Level 3 [Member] | Measurement Input, Spread [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 67.44          
Maximum [Member] | Commodity Contract [Member] | Natural Gas [Member] | Level 3 [Member] | Measurement Input, Spread [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs | MMBTU 3.92   2.13      
Maximum [Member] | Commodity Contract [Member] | Oil [Member] | Level 3 [Member] | Measurement Input, Spread [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 12.53   11.20      
Maximum [Member] | Equity Contract [Member] | Level 3 [Member] | Measurement Input, Correlation [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 1   1      
Maximum [Member] | Equity Contract [Member] | Level 3 [Member] | Measurement Input, Price Volatility [Member]            
Fair Value Measurement Inputs Disclosure [Line Items]            
Assets (Liabilities) significant unobservable Inputs 1.54   1.29