v3.22.0.1
Shareholders' Equity - Accumulated Other Comprehensive Income/(Loss), Net of Tax (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]      
Beginning balance $ 95,932 $ 90,265  
Other comprehensive income/(loss) adjustments, net of tax (634) 50 $ (2,177)
Ending balance 109,926 95,932 90,265
Currency Translation [Member]      
Accumulated Other Comprehensive Income (Loss) [Line Items]      
Beginning balance (696) (616) (621)
Other comprehensive income/(loss) adjustments, net of tax (42) (80) 5
Ending balance (738) (696) (616)
Debt Valuation Adjustment [Member]      
Accumulated Other Comprehensive Income (Loss) [Line Items]      
Beginning balance (833) (572) 1,507
Other comprehensive income/(loss) adjustments, net of tax 322 (261) (2,079)
Ending balance (511) (833) (572)
Pension and Postretirement Liabilities [Member]      
Accumulated Other Comprehensive Income (Loss) [Line Items]      
Beginning balance (368) (342) (81)
Other comprehensive income/(loss) adjustments, net of tax 41 (26) (261)
Ending balance (327) (368) (342)
Available-for-sale Securities [Member]      
Accumulated Other Comprehensive Income (Loss) [Line Items]      
Beginning balance 463 46 (112)
Other comprehensive income/(loss) adjustments, net of tax (955) 417 158
Ending balance (492) 463 46
Accumulated Other Comprehensive Income (Loss) [Member]      
Accumulated Other Comprehensive Income (Loss) [Line Items]      
Beginning balance (1,434) (1,484) 693
Other comprehensive income/(loss) adjustments, net of tax (634) 50 (2,177)
Ending balance $ (2,068) $ (1,434) $ (1,484)