Stockholders' Equity (Narrative) (Detail) $ / shares in Units, shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) $ / shares shares	Sep. 30, 2019 USD ($)
Stockholders Equity [Line Items]
Currency translation adjustments (net of tax of $12, $(12), $12, and $(14), respectively)	$ 35,000,000	$ (31,000,000)	$ (9,000,000)	$ (21,000,000)
Other Comprehensive Income Unrealized Gain Loss On Cash Flow Hedges Arising During Period Net Of Tax			(38,000,000)	(23,000,000)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax			5,000,000	(2,000,000)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax			(33,000,000)	$ (25,000,000)
Option Premiums Paid		16,000,000
Stockholders' Equity Note [Abstract]
Option Premiums Paid		$ 16,000,000
Open Option Contracts Written, Number of Shares		600,000		600,000
Stock Repurchase Program, Authorized Amount	1,800,000,000		$ 1,800,000,000
Stock Repurchased During Period, Shares | shares			5.0
Stock Repurchased During Period, Value			$ 113,000,000
Stock Repurchased During Period, Average Price | $ / shares			$ 22.49
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 76,000,000		$ 76,000,000
Proceeds from Issuance of Common Stock			$ 15,000,000	$ 0
Additional Paid-in Capital [Member]
Stockholders Equity [Line Items]
Option Premiums Paid		$ 16,000,000		(16,000,000)
Stockholders' Equity Note [Abstract]
Option Premiums Paid		$ 16,000,000		$ (16,000,000)