Condensed Consolidated Statements of Changes in Equity - USD ($) $ in Millions		Total	Common Stock		Additional paid-in capital	Treasury Stock	Retained Earnings	Accumulated Other Comprehensive Loss	Total Stockholders' Equity	Non controlling Interests
Balance at Dec. 31, 2015		$ 15,066	$ 3		$ 13,653		$ 1,449	$ (52)	$ 15,053	$ 13
Balance, shares at Dec. 31, 2015	[1]		308,864,609
Net Income		423					423		423
Other comprehensive income (loss), net of tax		(32)						(32)	(32)
Comprehensive Income		391
Dividends declared		$ (401)					(401)		(401)
Release of common stock held in trust		134,921	134,921	[1]
Issuance of common stock, issuance costs		$ (2)			(2)				(2)
Issuance of common stock, shares		101,538	101,538	[1]
Repurchase of common stock		$ (4)				$ (4)			(4)
Repurchase of common stock, shares	[1]		(97,479)
Stock-based compensation		1			1				1
Balance at Sep. 30, 2016		15,051	$ 3		13,652	(4)	1,471	(84)	15,038	13
Balance, shares at Sep. 30, 2016	[1]		309,003,589
Balance at Dec. 31, 2015		$ 15,066	$ 3		13,653		1,449	(52)	15,053	13
Balance, shares at Dec. 31, 2015	[1]		308,864,609
Repurchase of common stock, shares		(115,831)
Balance at Dec. 31, 2016		$ 15,122	$ 3		13,653	(5)	1,544	(86)	15,109	13
Balance, shares at Dec. 31, 2016		308,993,149	308,993,149	[1]
Net Income		$ 459					458		458	1
Other comprehensive income (loss), net of tax		32						32	32
Comprehensive Income		491
Dividends declared		$ (401)					(401)		(401)
Release of common stock held in trust		5,649	5,649	[1]
Issuance of common stock, issuance costs		$ (1)			(1)				(1)
Issuance of common stock, shares		70,493	70,493	[1]
Repurchase of common stock		$ (3)				(3)			(3)
Repurchase of common stock, shares	[1]		(64,019)
Stock-based compensation		4			4				4
Transaction with noncontrolling interests		5					4		4	1
Balance at Sep. 30, 2017		$ 15,217	$ 3		$ 13,656	$ (8)	$ 1,605	$ (54)	$ 15,202	$ 15
Balance, shares at Sep. 30, 2017		309,005,272	309,005,272	[1]

[1] Par value of share amounts is $0.01