Consolidated Statement of Shareholder's Interest - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Shareholder's Interest [Roll Forward]
Net income				$ 239			$ 982	$ 765
Balance at end of period	$ 14,030						14,030
Shareholder's Interest [Member]
Shareholder's Interest [Roll Forward]
Balance at beginning of period	5,166	$ 5,166	$ 5,166	5,166	$ 5,166	$ 5,166	5,166	5,166
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	5,166	5,166	5,166	5,166	5,166	5,166	5,166	5,166
Accumulated Other Comprehensive Income/(Loss) (Note11) [Member]
Shareholder's Interest [Roll Forward]
Balance at beginning of period	(1,003)	(949)	(829)	(911)	(929)	(1,017)	(829)	(1,017)
Net income	0	0	0	0	0	0
Other Comprehensive Income (Loss), Net of Tax	158	(54)	(120)	(124)	18	88
Distributions declared	0	0	0	0	0	0
Balance at end of period	(845)	(1,003)	(949)	(1,035)	(911)	(929)	(845)	(1,035)
Retained Earnings [Member]
Shareholder's Interest [Roll Forward]
Balance at beginning of period	9,391	9,286	9,052	8,254	7,968	7,728	9,052	7,728
Net income	493	255	234	239	286	240
Other Comprehensive Income (Loss), Net of Tax	0	0	0	0	0	0
Distributions declared	(175)	(150)	0	0	0	0
Balance at end of period	9,709	9,391	9,286	8,493	8,254	7,968	9,709	8,493
Parent [Member]
Shareholder's Interest [Roll Forward]
Balance at beginning of period	13,554	13,503	13,389	12,509	12,205	11,877	13,389	11,877
Net income	493	255	234	239	286	240
Other Comprehensive Income (Loss), Net of Tax	158	(54)	(120)	(124)	18	88
Distributions declared	(175)	(150)	0	0	0	0
Balance at end of period	$ 14,030	$ 13,554	$ 13,503	$ 12,624	$ 12,509	$ 12,205	$ 14,030	$ 12,624