Shareholders' Equity (Shareholders' Equity Activity) (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended					6 Months Ended
	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2017	Jun. 30, 2016	Jun. 07, 2016
Schedule of Issued and Treasury Shares [Line Items]
Capital in Excess of Par Value	$ 6,612		$ 6,571			$ 6,612
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning balance		$ 2,068			$ 4,365	2,068	$ 4,365
Net Income (Loss)	(165)			$ (562)		(608)	(1,053)
Other Comprehensive Income	(10)	33		(9)	134	33	134
Dividends Paid to Noncontrolling Interests						(10)	(7)
Issuance of Common Shares				623			623
Adjustments to Additional Paid in Capital, Convertible Debt with Conversion Feature							97
Equity Awards Granted, Vested and Exercised						41	28
Balance, ending balance	1,524		2,068	4,187		1,524	4,187
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		6,571			$ 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						41	28
Balance, ending balance	6,612		$ 6,571	6,250		6,612	6,250
Stock issued during period, shares, new issues			84.5		115.0
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning balance		(2,950)			$ 442	(2,950)	442
Net Income (Loss)						(619)	(1,063)
Adjustments to Additional Paid in Capital, Convertible Debt with Conversion Feature							0
Equity Awards Granted, Vested and Exercised						0	0
Balance, ending balance	(3,569)		$ (2,950)	(621)		(3,569)	(621)
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning balance		(1,610)			(1,641)	(1,610)	(1,641)
Other Comprehensive Income						33	134
Adjustments to Additional Paid in Capital, Convertible Debt with Conversion Feature							0
Equity Awards Granted, Vested and Exercised						0	0
Balance, ending balance	(1,577)		(1,610)	(1,507)		(1,577)	(1,507)
Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning balance		$ 56			61	56	61
Net Income (Loss)						11	10
Dividends Paid to Noncontrolling Interests						(10)	(7)
Adjustments to Additional Paid in Capital, Convertible Debt with Conversion Feature							0
Equity Awards Granted, Vested and Exercised						0	0
Balance, ending balance	$ 57		$ 56	$ 64		$ 57	$ 64
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