Shareholders' Equity (Deficiency) (Shareholders' Equity Activity) (Details) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning balance	$ 1,305	$ 1,863	$ 2,916	$ (4,389)	$ (4,106)	$ (3,666)	$ 2,916	$ (3,666)
Net Income (Loss)	(167)	(579)	(958)	(815)	(312)	(477)	(1,704)	(1,604)
Other Comprehensive Income	(6)	29	(95)	(20)	30	33	(72)	43
Dividends Paid to Noncontrolling Interests	(9)	(8)		(5)	(6)	(5)
Equity Awards Granted, Vested and Exercised				5	5	8
Other						1
Balance, ending balance	1,123	1,305	1,863	(5,224)	(4,389)	(4,106)	1,123	(5,224)
Par Value of Issued Shares
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning balance	0	0	0	1	1	1	0	1
Balance, ending balance	0	0	0	1	1	1	0	1
Capital in Excess of Par Value
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning balance	2,897	2,897	2,897	6,724	6,719	6,711	2,897	6,711
Equity Awards Granted, Vested and Exercised				5	5	8
Balance, ending balance	2,897	2,897	2,897	6,729	6,724	6,719	2,897	6,729
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning balance	(1,573)	(992)	(26)	(9,468)	(9,152)	(8,671)	(26)	(8,671)
Net Income (Loss)	(174)	(581)	(966)	(821)	(316)	(481)
Balance, ending balance	(1,747)	(1,573)	(992)	(10,289)	(9,468)	(9,152)	(1,747)	(10,289)
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning balance	(57)	(86)	9	(1,683)	(1,713)	(1,746)	9	(1,746)
Other Comprehensive Income	(6)	29	(95)	(20)	30	33
Balance, ending balance	(63)	(57)	(86)	(1,703)	(1,683)	(1,713)	(63)	(1,703)
Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning balance	38	44	36	37	39	39	36	39
Net Income (Loss)	7	2	8	6	4	4
Dividends Paid to Noncontrolling Interests	(9)	(8)		(5)	(6)	(5)
Other						1
Balance, ending balance	$ 36	$ 38	$ 44	$ 38	$ 37	$ 39	$ 36	$ 38