Statement of Changes in Consolidated Equity - USD ($) $ in Millions	Total	Preferred Class A	Preferred Class B	Preferred stock	Mandatory convertible preferred stock	Common stock	Additional capital	Retained earnings (accumulated deficit)	Retained earnings (accumulated deficit) Preferred Class A	Retained earnings (accumulated deficit) Preferred Class B	Accumulated Other Comprehensive Loss	Noncontrolling Interests
Balance at beginning of period at Dec. 31, 2016	$ 5,141			$ 55	$ 3	$ 438	$ 8,214	$ (1,027)			$ (2,568)	$ 26
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(74)							(74)				0
Other comprehensive (loss) income (J)	(74)										(76)	2
Cash dividends declared:
Cash dividends declared, preferred		$ (2)	$ (51)						$ (2)	$ (51)
Cash dividends declared, common	(109)							(109)
Stock-based compensation (H)	67						67
Common stock issued: compensation plans (H)	21						21
Conversion of mandatory convertible preferred stock (H)	0				(3)	39	(36)
Issuance of common stock (H)	4					4
Distributions	(14)											(14)
Other	15							15
Balance at end of period at Dec. 31, 2017	4,924			55	0	481	8,266	(1,248)			(2,644)	14
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	642							642				0
Other comprehensive (loss) income (J)	85										85
Cash dividends declared:
Cash dividends declared, preferred		(2)							(2)
Cash dividends declared, common	(117)							(117)
Stock-based compensation (H)	50						50
Common stock issued: compensation plans (H)	5						3
Issuance of common stock (H)						2
Other	(2)							0				(2)
Balance at end of period at Dec. 31, 2018	5,585			55	0	483	8,319	(358)			(2,926)	12
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	470							470				0
Other comprehensive (loss) income (J)	(401)										(401)
Cash dividends declared:
Cash dividends declared, preferred		$ (2)							$ (2)
Cash dividends declared, common	(56)							(56)
Repurchase and retirement of common stock (H)	(1,150)					(55)	(1,095)
Stock-based compensation (H)	57						57
Common stock issued: compensation plans (H)	41					5	36
Other	4						2					2
Balance at end of period at Dec. 31, 2019	$ 4,621			$ 55	$ 0	$ 433	$ 7,319	$ 129			$ (3,329)	$ 14