Other Comprehensive Loss - Components of Accumulated Other Comprehensive Loss (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Equity [Abstract]
Unrealized gains (losses) on available-for-sale securities, tax benefit		$ 2
Unrealized gains (losses) on available-for-sale securities, tax expense	$ 4
Foreign currency translation adjustments, income tax benefit		8
Foreign currency translation adjustments, income tax expense	5		$ 35
Defined benefit plans, income tax benefit	14		10
Defined benefit plans, income tax expense		10
Change in fair value of derivative instruments, income tax benefit	13
Change in fair value of derivative instruments, income tax expense		5	4
Unrealized gains on available-for-sale securities, expense reclassified into operations from other comprehensive income			1
Defined benefit plans, benefit reclassified into operations from other comprehensive income	3	5	7
Interest expense on derivative instruments, benefit reclassified into operations from other comprehensive income			$ 7
Interest benefit on derivative instruments, expense reclassified into operations from other comprehensive income	$ 3	$ 2