Shareholders' (Deficiency) Equity (Shareholders' Equity Activity) (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Jan. 01, 2018
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning balance	$ (4,106)	$ (3,666)	$ (898)	$ (571)	$ (3,666)	$ (571)
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets							$ (97)
Net Income (Loss)	(312)	(477)	(259)	(242)	(789)	(501)
Other Comprehensive Income	30	33	(165)	5	63	(160)
Dividends Paid to Noncontrolling Interests	(6)	(5)	(2)	(4)
Equity Awards Granted, Vested and Exercised	5	8	12	17
Stockholders' Equity, Other	0	1		(6)
Balance, ending balance	(4,389)	(4,106)	(1,312)	(898)	(4,389)	(1,312)
Par Value of Issued Shares
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning balance	1	1	1	1	1	1
Equity Awards Granted, Vested and Exercised	0		0
Balance, ending balance	1	1	1	1	1	1
Capital in Excess of Par Value
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning balance	6,719	6,711	6,676	6,655	6,711	6,655
Equity Awards Granted, Vested and Exercised	5	8	12	17
Stockholders' Equity, Other	0			4
Balance, ending balance	6,724	6,719	6,688	6,676	6,724	6,688
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning balance	(9,152)	(8,671)	(6,105)	(5,763)	(8,671)	(5,763)
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets							$ (97)
Net Income (Loss)	(316)	(481)	(264)	(245)
Equity Awards Granted, Vested and Exercised	0		0
Stockholders' Equity, Other	0
Balance, ending balance	(9,468)	(9,152)	(6,369)	(6,105)	(9,468)	(6,369)
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning balance	(1,713)	(1,746)	(1,514)	(1,519)	(1,746)	(1,519)
Other Comprehensive Income	30	33	(165)	5
Equity Awards Granted, Vested and Exercised	0		0
Balance, ending balance	(1,683)	(1,713)	(1,679)	(1,514)	(1,683)	(1,679)
Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning balance	39	39	44	55	39	55
Net Income (Loss)	4	4	5	3
Dividends Paid to Noncontrolling Interests	(6)	(5)	(2)	(4)
Equity Awards Granted, Vested and Exercised			0
Stockholders' Equity, Other	0	1		(10)
Balance, ending balance	$ 37	$ 39	$ 47	$ 44	$ 37	$ 47