v3.20.4
Accumulated Other Comprehensive Income (Loss) - Changes in AOCI (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]      
Balance $ 33,613 $ 32,433 $ 31,848
Foreign currency translation adjustments [1] 234 120 (253)
Balance 35,334 33,613 32,433
Accumulated Other Comprehensive Income (Loss) [Member]      
Accumulated Other Comprehensive Income (Loss) [Line Items]      
Balance (571) (691) (432)
Foreign currency translation adjustments [1] 234 120 (253)
Reclassification as a result of adoption of accounting guidance     (6)
Balance $ (337) $ (571) $ (691)
[1]

Amount for 2020 includes a loss from a net investment hedge of $54 million (net of tax benefit of $17 million). Amounts for 2019 and 2018 include gains from a net investment hedge of $11 million (net of tax expense of $3 million) and $30 million (net of tax expense of $10 million), respectively.