Shareholders' Equity (Shareholders' Equity Activity) (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Mar. 31, 2016	Sep. 30, 2017	Sep. 30, 2016	Jun. 07, 2016
Schedule of Issued and Treasury Shares [Line Items]
Capital in Excess of Par Value	$ 6,641	$ 6,571			$ 6,641
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning balance		2,383		$ 4,365	2,068	$ 4,365
Net Income (Loss)	(251)		$ (1,776)		(859)	(2,829)
Other Comprehensive Income	88		(42)		121	92
Dividends Paid to Noncontrolling Interests					(16)	(15)
Issuance of Common Shares			623			623
Adjustments to Additional Paid in Capital, Convertible Debt with Conversion Feature						97
Equity Awards Granted, Vested and Exercised					70	51
Balance, ending balance	1,384	2,068	2,383		1,384	2,383
Stockholders' Equity, Other						1
Par Value of Issued Shares
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning balance		1		1	1	1
Adjustments to Additional Paid in Capital, Convertible Debt with Conversion Feature						0
Equity Awards Granted, Vested and Exercised					0	0
Balance, ending balance	1	1	1		1	1
Capital in Excess of Par Value
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning balance		6,273		$ 5,502	6,571	5,502
Issuance of Common Shares			623			623
Adjustments to Additional Paid in Capital, Convertible Debt with Conversion Feature						97
Equity Awards Granted, Vested and Exercised					70	51
Balance, ending balance	6,641	$ 6,571	6,273		6,641	6,273
Stock issued during period, shares, new issues		84.5		115.0
Stockholders' Equity, Other						0
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning balance		$ (2,401)		$ 442	(2,950)	442
Net Income (Loss)					(875)	(2,843)
Adjustments to Additional Paid in Capital, Convertible Debt with Conversion Feature						0
Equity Awards Granted, Vested and Exercised					0	0
Balance, ending balance	(3,825)	(2,950)	(2,401)		(3,825)	(2,401)
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning balance		(1,549)		(1,641)	(1,610)	(1,641)
Other Comprehensive Income					121	92
Adjustments to Additional Paid in Capital, Convertible Debt with Conversion Feature						0
Equity Awards Granted, Vested and Exercised					0	0
Balance, ending balance	(1,489)	(1,610)	(1,549)		(1,489)	(1,549)
Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning balance		59		61	56	61
Net Income (Loss)					16	14
Dividends Paid to Noncontrolling Interests					(16)	(15)
Adjustments to Additional Paid in Capital, Convertible Debt with Conversion Feature						0
Equity Awards Granted, Vested and Exercised					0	0
Balance, ending balance	$ 56	$ 56	$ 59		$ 56	59
Stockholders' Equity, Other						$ 1
Sale of Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Additional paid in capital				$ 623
Exchangeable Debt [Member]
Schedule of Issued and Treasury Shares [Line Items]
Capital in Excess of Par Value							$ 97
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Debt Instrument, Face Amount							$ 1,265