v3.20.4
Derivatives and Hedging Activities - Credit Derivatives (Detail) - USD ($)
$ in Millions
Dec. 31, 2020
Dec. 31, 2019
Derivative [Line Items]    
Maximum Payout/Notional Amount of Written Credit Derivative $ 515,850 $ 522,569
Maximum Payout/Notional Amount of Purchased Credit Derivatives 558,180 581,760
Offsetting Purchased Credit Derivatives [Member]    
Derivative [Line Items]    
Maximum Payout/Notional Amount of Purchased Credit Derivatives 442,907 426,100
Other Purchased Credit Derivatives [Member]    
Derivative [Line Items]    
Maximum Payout/Notional Amount of Purchased Credit Derivatives 115,271 155,662
Less than 1 Year [Member]    
Derivative [Line Items]    
Maximum Payout/Notional Amount of Written Credit Derivative 104,728 154,433
1 - 5 Years [Member]    
Derivative [Line Items]    
Maximum Payout/Notional Amount of Written Credit Derivative 362,791 316,786
Greater than 5 Years [Member]    
Derivative [Line Items]    
Maximum Payout/Notional Amount of Written Credit Derivative 48,331 51,350
Written Credit Derivative [Member]    
Derivative [Line Items]    
Fair Value Asset of Written Credit Derivatives 11,314 13,911
Fair Value Liability of Written Credit Derivatives 4,619 5,549
Fair Value Net Asset/(Liability) of Written Credit Derivatives 6,695 8,362
0 - 250 [Member]    
Derivative [Line Items]    
Maximum Payout/Notional Amount of Written Credit Derivative 471,326 484,119
0 - 250 [Member] | Offsetting Purchased Credit Derivatives [Member]    
Derivative [Line Items]    
Maximum Payout/Notional Amount of Purchased Credit Derivatives 407,315 395,127
0 - 250 [Member] | Other Purchased Credit Derivatives [Member]    
Derivative [Line Items]    
Maximum Payout/Notional Amount of Purchased Credit Derivatives 103,604 149,092
0 - 250 [Member] | Less than 1 Year [Member]    
Derivative [Line Items]    
Maximum Payout/Notional Amount of Written Credit Derivative 96,049 143,566
0 - 250 [Member] | 1 - 5 Years [Member]    
Derivative [Line Items]    
Maximum Payout/Notional Amount of Written Credit Derivative 331,145 292,444
0 - 250 [Member] | Greater than 5 Years [Member]    
Derivative [Line Items]    
Maximum Payout/Notional Amount of Written Credit Derivative 44,132 48,109
0 - 250 [Member] | Written Credit Derivative [Member]    
Derivative [Line Items]    
Fair Value Asset of Written Credit Derivatives 10,302 13,103
Fair Value Liability of Written Credit Derivatives 1,112 1,239
Fair Value Net Asset/(Liability) of Written Credit Derivatives 9,190 11,864
251 - 500 [Member]    
Derivative [Line Items]    
Maximum Payout/Notional Amount of Written Credit Derivative 27,578 19,540
251 - 500 [Member] | Offsetting Purchased Credit Derivatives [Member]    
Derivative [Line Items]    
Maximum Payout/Notional Amount of Purchased Credit Derivatives 19,822 14,492
251 - 500 [Member] | Other Purchased Credit Derivatives [Member]    
Derivative [Line Items]    
Maximum Payout/Notional Amount of Purchased Credit Derivatives 7,272 2,617
251 - 500 [Member] | Less than 1 Year [Member]    
Derivative [Line Items]    
Maximum Payout/Notional Amount of Written Credit Derivative 5,826 7,155
251 - 500 [Member] | 1 - 5 Years [Member]    
Derivative [Line Items]    
Maximum Payout/Notional Amount of Written Credit Derivative 17,913 10,125
251 - 500 [Member] | Greater than 5 Years [Member]    
Derivative [Line Items]    
Maximum Payout/Notional Amount of Written Credit Derivative 3,839 2,260
251 - 500 [Member] | Written Credit Derivative [Member]    
Derivative [Line Items]    
Fair Value Asset of Written Credit Derivatives 638 446
Fair Value Liability of Written Credit Derivatives 1,119 448
Fair Value Net Asset/(Liability) of Written Credit Derivatives (481) (2)
501 - 1000 [Member]    
Derivative [Line Items]    
Maximum Payout/Notional Amount of Written Credit Derivative 9,523 6,668
501 - 1000 [Member] | Offsetting Purchased Credit Derivatives [Member]    
Derivative [Line Items]    
Maximum Payout/Notional Amount of Purchased Credit Derivatives 8,679 5,938
501 - 1000 [Member] | Other Purchased Credit Derivatives [Member]    
Derivative [Line Items]    
Maximum Payout/Notional Amount of Purchased Credit Derivatives 3,619 1,599
501 - 1000 [Member] | Less than 1 Year [Member]    
Derivative [Line Items]    
Maximum Payout/Notional Amount of Written Credit Derivative 450 759
501 - 1000 [Member] | 1 - 5 Years [Member]    
Derivative [Line Items]    
Maximum Payout/Notional Amount of Written Credit Derivative 8,801 5,482
501 - 1000 [Member] | Greater than 5 Years [Member]    
Derivative [Line Items]    
Maximum Payout/Notional Amount of Written Credit Derivative 272 427
501 - 1000 [Member] | Written Credit Derivative [Member]    
Derivative [Line Items]    
Fair Value Asset of Written Credit Derivatives 256 160
Fair Value Liability of Written Credit Derivatives 387 372
Fair Value Net Asset/(Liability) of Written Credit Derivatives (131) (212)
Greater than 1000 [Member]    
Derivative [Line Items]    
Maximum Payout/Notional Amount of Written Credit Derivative 7,423 12,242
Greater than 1000 [Member] | Offsetting Purchased Credit Derivatives [Member]    
Derivative [Line Items]    
Maximum Payout/Notional Amount of Purchased Credit Derivatives 7,091 10,543
Greater than 1000 [Member] | Other Purchased Credit Derivatives [Member]    
Derivative [Line Items]    
Maximum Payout/Notional Amount of Purchased Credit Derivatives 776 2,354
Greater than 1000 [Member] | Less than 1 Year [Member]    
Derivative [Line Items]    
Maximum Payout/Notional Amount of Written Credit Derivative 2,403 2,953
Greater than 1000 [Member] | 1 - 5 Years [Member]    
Derivative [Line Items]    
Maximum Payout/Notional Amount of Written Credit Derivative 4,932 8,735
Greater than 1000 [Member] | Greater than 5 Years [Member]    
Derivative [Line Items]    
Maximum Payout/Notional Amount of Written Credit Derivative 88 554
Greater than 1000 [Member] | Written Credit Derivative [Member]    
Derivative [Line Items]    
Fair Value Asset of Written Credit Derivatives 118 202
Fair Value Liability of Written Credit Derivatives 2,001 3,490
Fair Value Net Asset/(Liability) of Written Credit Derivatives $ (1,883) $ (3,288)