Components of Equity (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Stockholders Equity Note [Line Items]
Beginning Balance	$ 6,150	$ 7,070	$ 6,326	$ 7,325
Net loss	(60)	(352)	(212)	(355)
Net loss	(60)	(353)	(212)	(356)
Issuance of common stock for comprehensive stock plans, net	6	6	2	1
Repurchase of common stock				(147)
Dividends declared on common stock				(141)
Common stock issuances	138		138
Changes in ownership and other	(3)	1	(20)	58
Other comprehensive income/(loss)	6	(2)	3	(18)
Ending Balance	6,237	6,722	6,237	6,722
Common Stock
Stockholders Equity Note [Line Items]
Beginning Balance	7	7	7	7
Ending Balance	7	7	7	7
Additional Paid-in Capital
Stockholders Equity Note [Line Items]
Beginning Balance	7,547	7,580	7,568	7,675
Issuance of common stock for comprehensive stock plans, net	6	6	2	1
Repurchase of common stock				(147)
Common stock issuances	138		138
Changes in ownership and other	(3)		(20)	57
Ending Balance	7,688	7,586	7,688	7,586
Accumulated Other Comprehensive Income (Loss)
Stockholders Equity Note [Line Items]
Beginning Balance	(77)	(72)	(74)	(56)
Other comprehensive income/(loss)	6	(2)	3	(18)
Ending Balance	(71)	(74)	(71)	(74)
Retained Earnings / (Deficit)
Stockholders Equity Note [Line Items]
Beginning Balance	(1,332)	(451)	(1,180)	(307)
Net loss	(60)	(352)	(212)	(355)
Dividends declared on common stock				(141)
Changes in ownership and other		1		1
Ending Balance	(1,392)	(802)	(1,392)	(802)
Non-redeemable, non-controlling interests
Stockholders Equity Note [Line Items]
Beginning Balance	5	6	5	6
Net income attributable to non-controlling interests		(1)		(1)
Ending Balance	5	5	5	5
Redeemable, non-controlling interests
Stockholders Equity Note [Line Items]
Beginning Balance	124	84	108	142
Net loss	(1)	(3)	(2)	(3)
Distributions to non-controlling interests				(2)
Changes in ownership and other	2		19	(56)
Ending Balance	$ 125	$ 81	$ 125	$ 81