Consolidated Statement of Shareholder's Interest - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Shareholder's Interest [Roll Forward]
Balance at beginning of period	$ 13,389
Net income	234	$ 240
Balance at end of period	13,503
Shareholder's Interest [Member]
Shareholder's Interest [Roll Forward]
Balance at beginning of period	5,166	5,166
Net income	0	0
Other Comprehensive Income (Loss), Net of Tax	0	0
Distributions declared	0	0
Balance at end of period	5,166	5,166
Accumulated Other Comprehensive Income/(Loss) (Note11) [Member]
Shareholder's Interest [Roll Forward]
Balance at beginning of period	(829)	(1,017)
Net income	0	0
Other Comprehensive Income (Loss), Net of Tax	(120)	88
Distributions declared	0	0
Balance at end of period	(949)	(929)
Retained Earnings [Member]
Shareholder's Interest [Roll Forward]
Balance at beginning of period	9,052	7,728
Other Comprehensive Income (Loss), Net of Tax	0	0
Distributions declared	0	0
Balance at end of period	9,286	7,968
Parent [Member]
Shareholder's Interest [Roll Forward]
Net income	234	240
Other Comprehensive Income (Loss), Net of Tax	(120)	88
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Beginning Balance		11,877
Distributions declared	0	0
Balance at end of period	$ 13,503
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Ending Balance		$ 12,205