v3.19.3.a.u2
Financial Instruments - Long-Term Debt (Details) - USD ($)
$ in Millions
Dec. 31, 2019
Dec. 31, 2018
Mar. 31, 2017
Debt Instrument [Line Items]      
Net fair value adjustments related to hedging and purchase accounting $ 5 $ (5)  
Net unamortized discounts, premiums and debt issuance costs (43) (11)  
Total long-term debt, carried at historical proceeds, as adjusted 35,955 32,909  
Current portion of long-term debt, carried at historical proceeds (not included above (1.2% and 1.3%)) [1] $ 1,462 $ 4,776  
Unsecured Debt [Member]      
Debt Instrument [Line Items]      
Interest rate, percentage 1.20% 1.30% 0.23%
Total principal amount of long-term debt $ 34,820 $ 32,558  
Net fair value adjustments related to hedging and purchase accounting 1,305 479  
Net unamortized discounts, premiums and debt issuance costs (176) (136)  
Other long-term debt 5 7  
Total long-term debt, carried at historical proceeds, as adjusted 35,955 32,909  
Current portion of long-term debt, carried at historical proceeds (not included above (1.2% and 1.3%)) 1,462 4,776  
Unsecured Debt [Member] | Senior Unsecured Debt, Due 2020 [Member]      
Debt Instrument [Line Items]      
Total principal amount of long-term debt $ 0 $ 1,474  
Unsecured Debt [Member] | Senior Unsecured Debt, Due 2021 [Member]      
Debt Instrument [Line Items]      
Interest rate, percentage 0.70% 3.40%  
Total principal amount of long-term debt $ 3,153 $ 4,459  
Unsecured Debt [Member] | Senior Unsecured Debt, Due 2022 [Member]      
Debt Instrument [Line Items]      
Interest rate, percentage 1.00% 0.30%  
Total principal amount of long-term debt $ 1,624 $ 1,145  
Unsecured Debt [Member] | Senior Unsecured Debt, Due 2023 [Member]      
Debt Instrument [Line Items]      
Interest rate, percentage 3.70% 3.80%  
Total principal amount of long-term debt $ 2,892 $ 2,892  
Unsecured Debt [Member] | Senior Unsecured Debt, Due 2024 [Member]      
Debt Instrument [Line Items]      
Interest rate, percentage 3.90% 4.40%  
Total principal amount of long-term debt $ 2,250 $ 1,500  
Unsecured Debt [Member] | Senior Unsecured Debt, Due 2026-2029 [Member]      
Debt Instrument [Line Items]      
Interest rate, percentage 3.30%    
Total principal amount of long-term debt $ 7,453 5,718  
Unsecured Debt [Member] | Senior Unsecured Debt, Due 2034 [Member]      
Debt Instrument [Line Items]      
Interest rate, percentage 6.50%    
Total principal amount of long-term debt $ 750 $ 750  
Unsecured Debt [Member] | Senior Unsecured Debt, Due 2036-2040 [Member]      
Debt Instrument [Line Items]      
Interest rate, percentage 5.80% 6.00%  
Total principal amount of long-term debt $ 8,566 $ 7,796  
Unsecured Debt [Member] | Senior Unsecured Debt, Due 2043-2044 [Member]      
Debt Instrument [Line Items]      
Interest rate, percentage 3.50%    
Total principal amount of long-term debt $ 3,568 $ 3,509  
Unsecured Debt [Member] | Senior Unsecured Debt, Due 2046-2049 [Member]      
Debt Instrument [Line Items]      
Interest rate, percentage 4.10% 4.20%  
Total principal amount of long-term debt $ 4,565 $ 3,315  
[1]
Amounts may not add due to rounding.