Income Taxes - Additional Information (Detail) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
---|---|---|---|---|
Jun. 30, 2021 |
Jun. 30, 2020 |
Jun. 30, 2021 |
Jun. 30, 2020 |
|
Income Tax Disclosure [Abstract] | ||||
Effective tax rate benefit | 21.00% | 22.30% | 22.10% | 12.10% |
IRS | ||||
Income Tax Examination [Line Items] | ||||
Possible increase in U.S. taxable income | $ 696 | |||
Possible additional federal tax expense | $ 244 |