Consolidated Statement of Shareholder's Interest - USD ($) $ in Millions		3 Months Ended						9 Months Ended
	Jan. 01, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Shareholder's Interest [Roll Forward]
Net income		$ (980)	$ (1,651)	$ (845)	$ (1,041)	$ (476)	$ 6	$ (3,476)	$ (1,511)
Other Comprehensive Income (Loss), Net of Tax		(179)	108	(101)	238	87	(348)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Beginning Balance	$ 15,567	13,070	15,311	15,567	15,187	15,450	16,389	15,567	16,389
Distributions declared		1,500	4,000	1,000	831	826	343
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Ending Balance		12,371	13,070	15,311	15,635	15,187	15,450	12,371	15,635
Accounting Standards Update 2019-12, 2016-13
Shareholder's Interest [Roll Forward]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Ending Balance					(242)				(242)
Shareholder's Interest [Member]
Shareholder's Interest [Roll Forward]
Balance at beginning of period	5,227	5,227	5,227	5,227	5,227	5,227	5,227	5,227	5,227
Net income		0	0	0	0	0	0
Other Comprehensive Income (Loss), Net of Tax		0	0	0	0	0	0
Distributions declared		0	0	0	0	0	0
Balance at end of period		5,227	5,227	5,227	5,227	5,227	5,227	5,227	5,227
Shareholder's Interest [Member] | Accounting Standards Update 2019-12, 2016-13
Shareholder's Interest [Roll Forward]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Ending Balance					0				0
Accumulated Other Comprehensive Income/(Loss) (Note11) [Member]
Shareholder's Interest [Roll Forward]
Balance at beginning of period	(478)	(471)	(579)	(478)	(1,111)	(1,198)	(850)	(478)	(850)
Net income		0	0	0	0	0	0
Other Comprehensive Income (Loss), Net of Tax		(179)	108	(101)	238	87	(348)
Distributions declared		0	0	0	0	0	0
Balance at end of period		(650)	(471)	(579)	(873)	(1,111)	(1,198)	(650)	(873)
Accumulated Other Comprehensive Income/(Loss) (Note11) [Member] | Accounting Standards Update 2019-12, 2016-13
Shareholder's Interest [Roll Forward]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Ending Balance					0				0
Retained Earnings [Member]
Shareholder's Interest [Roll Forward]
Balance at beginning of period	10,818	8,314	10,663	10,818	11,071	11,421	12,012	10,818	12,012
Net income		(980)	(1,651)	(845)	(1,041)	(476)	(6)
Other Comprehensive Income (Loss), Net of Tax		0	0	0	0	0	0
Distributions declared		1,500	4,000	1,000	831	826	343
Balance at end of period		$ 7,794	$ 8,314	$ 10,663	11,281	$ 11,071	$ 11,421	$ 7,794	11,281
Retained Earnings [Member] | Accounting Standards Update 2019-12
Shareholder's Interest [Roll Forward]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Ending Balance	(40)
Retained Earnings [Member] | Accounting Standards Update 2019-12, 2016-13
Shareholder's Interest [Roll Forward]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Ending Balance	$ (242)				$ (242)				$ (242)