Consolidated Statements of Changes in Equity - USD ($) shares in Thousands, $ in Millions	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Total Stockholders’ Equity	Non-controlling Interests	Series A Preferred Stock	Series A Preferred Stock Preferred Stock	Series A Preferred Stock Common Stock	Series A Preferred Stock Additional Paid-In Capital
Balance at beginning of period (in shares) at Dec. 31, 2016		111,087							72
Balance at beginning of period at Dec. 31, 2016	$ 3,038	$ 0	$ 3,245	$ (393)	$ (194)	$ 2,700	$ 338		$ 42
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	360			340		340	20
Other comprehensive (loss) income	275				223	223	52
Exercise and vesting of stock compensation awards (in shares)		728
Exercise and vesting of stock compensation awards	1		1			1
Tax withholdings related to vesting of stock compensation awards	(17)		(17)			(17)
Issuance of common stock (in shares)		5,000
Issuance of common stock	288		288			288
Conversion of Series A preferred stock to common stock								$ 0	$ (1)		$ 1
Conversion of Series A preferred stock to common stock (in shares)										103
Issuance of common stock upon conversion of convertible senior notes, net of tax (in shares)		3,002
Issuance of common stock upon conversion of convertible senior notes, net of tax	49		49			49
Dividend paid	(7)			(3)		(3)	(4)
Impact of tax reform act	0			13	(13)
Stock compensation expense	23		23			23
Balance at end of period (in shares) at Dec. 31, 2017		119,920							72
Balance at end of period at Dec. 31, 2017	4,010	$ 0	3,590	(43)	16	3,604	406		$ 41
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	444			422		422	22
Other comprehensive (loss) income	(197)				(170)	(170)	(27)
Exercise and vesting of stock compensation awards (in shares)		995
Exercise and vesting of stock compensation awards	1		1			1
Tax withholdings related to vesting of stock compensation awards	(53)		(53)			(53)
Issuance of common stock (in shares)		6,000
Issuance of common stock	349		349			349
Retirement of common stock (in shares)		(11,314)
Retirement of common stock	(608)		(608)			(608)
Dividend paid	(9)			(3)		(3)	(6)
Stock compensation expense	30		30			30
Adoption of new accounting standard and other (in shares)		82
Adoption of new accounting standard and other	3		2	1		3
Balance at end of period (in shares) at Dec. 31, 2018		115,683							72
Balance at end of period at Dec. 31, 2018	3,970	$ 0	3,311	377	(154)	3,575	395		$ 41
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	440			419		419	21
Other comprehensive (loss) income	8				9	9	(1)
Exercise and vesting of stock compensation awards (in shares)		489
Exercise and vesting of stock compensation awards	1		1			1
Tax withholdings related to vesting of stock compensation awards	(14)		(14)			(14)
Purchase of noncontrolling interests	(258)		(3)			(3)	(255)
Retirement of common stock (in shares)		(23,932)
Retirement of common stock	(1,275)		(1,275)			(1,275)
Dividend paid	(8)			(3)		(3)	(5)
Stock compensation expense	36		36			36
Adoption of new accounting standard and other (in shares)		102
Adoption of new accounting standard and other	(4)		5	(7)		(2)	(2)
Balance at end of period (in shares) at Dec. 31, 2019		92,342							72
Balance at end of period at Dec. 31, 2019	$ 2,896	$ 0	$ 2,061	$ 786	$ (145)	$ 2,743	$ 153		$ 41