v3.20.4
Income Taxes - Reconciliation of Income Tax Expense with Expected Federal Income Tax Expense (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Income Tax Disclosure [Abstract]      
Statutory income tax expense, amount $ 1,296 $ 1,205 $ 1,130
State and local taxes (net of federal benefit), amount 81 96 99
Impact of federal, foreign, state, and local tax rate changes on deferred taxes, amount 78 5  
Stock-based compensation awards, amount (36) (23) (64)
Charitable Contribution, amount (128)    
Effect of foreign tax rates, amount (100) (76) (119)
Other, amount 47 54 30
Total income tax expense $ 1,238 $ 1,261 $ 1,076
Statutory income tax expense, rate 21.00% 21.00% 21.00%
State and local taxes (net of federal benefit), rate 1.00% 2.00% 2.00%
Impact of federal, foreign, state, and local tax rate changes on deferred taxes, rate 1.00%    
Stock-based compensation awards, rate     (1.00%)
Charitable Contribution, rate (2.00%)    
Effect of foreign tax rates, rate (2.00%) (1.00%) (2.00%)
Other, rate 1.00% 0.00% 0.00%
Effective income tax rate 20.00% 22.00% 20.00%