Shareholders' Equity (Deficiency) (Shareholders' Equity Activity) (Details) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning balance	$ 759	$ 821	$ 937	$ 1,305	$ 1,863	$ 2,916	$ 937	$ 2,916
Net Income (Loss)	(89)	(73)	(110)	(167)	(579)	(958)	(272)	(1,704)
Noncontrolling Interest, Change in Redemption Value	(2)	(2)	(2)
Other Comprehensive Income (Loss), Net of Tax	(11)	15	(4)	(6)	29	(95)
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders	(11)	(4)		(9)	(8)
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	1	2
Balance, ending balance	647	759	821	1,123	1,305	1,863	647	1,123
Capital in Excess of Par Value
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning balance	2,899	2,897		2,897	2,897	2,897		2,897
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	1	2
Balance, ending balance	2,900	2,899	2,897	2,897	2,897	2,897	2,900	2,897
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning balance	(2,141)	(2,063)		(1,573)	(992)	(26)		(26)
Net Income (Loss)	(95)	(78)	(116)	(174)	(581)	(966)
Balance, ending balance	(2,236)	(2,141)	(2,063)	(1,747)	(1,573)	(992)	(2,236)	(1,747)
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning balance	(32)	(47)		(57)	(86)	9		9
Other Comprehensive Income (Loss), Net of Tax	(11)	15	(4)	(6)	29	(95)
Balance, ending balance	(43)	(32)	(47)	(63)	(57)	(86)	(43)	(63)
Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning balance	33	34		38	44	36		36
Net Income (Loss)	6	5	6	7	2	8
Noncontrolling Interest, Change in Redemption Value	(2)	(2)	(2)
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders	(11)	(4)		(9)	(8)
Balance, ending balance	$ 26	$ 33	$ 34	$ 36	$ 38	$ 44	$ 26	$ 36