v3.19.3.a.u2
Income Taxes - Schedule of Changes to Gross Unrecognized Tax Benefits (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Income Tax Disclosure [Abstract]      
Unrecognized tax benefits, beginning balance $ 253 $ 199 $ 204
Decreases in balances related to prior year tax positions (39) (6) (31)
Increases in balances related to current year tax positions 59 60 84
Changes in balances related to effect of U.S. tax law change     (58)
Unrecognized tax benefits, ending balance $ 273 $ 253 $ 199