Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Millions		Total		Prior to Adoption	Effect of Adoption	Common Stock		Additional Paid-in Capital		Retained Earnings		Retained Earnings Prior to Adoption	Retained Earnings Effect of Adoption	Accumulated Other Comprehensive Loss		Accumulated Other Comprehensive Loss Prior to Adoption		Accumulated Other Comprehensive Loss Effect of Adoption		Treasury Stock
Total stockholder's equity at beginning of period at Dec. 31, 2021	[1]					$ 683		$ 2,215		$ 9,639		$ 9,663	$ (24)	$ (1,360)		$ 320		$ (1,680)		$ (72)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	[1]							(4)												17
Dividends to common stockholders ($0.42, $0.40, $2.46, $3.20 per share)	[1]									(876)
Net income		$ 443	[2],[3]	$ 646	$ (203)					443	[1]
Other comprehensive loss		(2,643)		(4,459)	1,816									(2,643)	[1]
Purchase of treasury stock		(39)																		(39)	[1]
Total stockholder's equity at end of period at Sep. 30, 2022	[1]	$ 8,003				683		2,211		9,206				(4,003)						(94)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per share (usd per share)		$ 3.20
Total stockholder's equity at beginning of period at Jun. 30, 2022						683	[1]	2,203	[1]	9,358	[1]	9,415	(57)	(3,163)	[1]	(2,713)	[1]	(450)	[1]	(76)	[1]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	[1]							8												0
Dividends to common stockholders ($0.42, $0.40, $2.46, $3.20 per share)	[1]									(110)
Net income		$ (42)	[2],[4]	128	(170)					(42)	[1]
Other comprehensive loss		(840)	[4]	(1,426)	586									(840)	[1]
Purchase of treasury stock	[1]																			(18)
Total stockholder's equity at end of period at Sep. 30, 2022	[1]	$ 8,003				683		2,211		9,206				(4,003)						(94)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per share (usd per share)		$ 0.40
Total stockholder's equity at beginning of period at Dec. 31, 2022		$ 8,548	[5]	$ 8,825	$ (277)	683		2,220		9,336		9,572	(236)	(3,598)		(3,557)		(41)		(93)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation								(7)												22
Dividends to common stockholders ($0.42, $0.40, $2.46, $3.20 per share)										(671)
Net income		838								838
Other comprehensive loss		(143)												(143)
Purchase of treasury stock		(24)																		(24)
Total stockholder's equity at end of period at Sep. 30, 2023		$ 8,563				683		2,213		9,503				(3,741)						(95)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per share (usd per share)		$ 2.46
Total stockholder's equity at beginning of period at Jun. 30, 2023						683		2,204		9,359		$ 9,359	$ 0	(3,425)		$ (3,425)		$ 0		(95)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation								9												0
Dividends to common stockholders ($0.42, $0.40, $2.46, $3.20 per share)										(114)
Net income		$ 258								258
Other comprehensive loss		(316)												(316)
Purchase of treasury stock																				0
Total stockholder's equity at end of period at Sep. 30, 2023		$ 8,563				$ 683		$ 2,213		$ 9,503				$ (3,741)						$ (95)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per share (usd per share)		$ 0.42

[1] As of January 1, 2023, the Company adopted ASU 2018-12 using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Condensed Consolidated Financial Statements for additional information.

[2] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Condensed Consolidated Financial Statements for additional information.

[3] As of January 1, 2023, the Company adopted ASU 2018-12 using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Condensed Consolidated Financial Statements for additional information.

[4] As of January 1, 2023, the Company adopted ASU 2018-12 using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Condensed Consolidated Financial Statements for additional information.

[5] As of January 1, 2023, the Company adopted ASU 2018-12 using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Condensed Consolidated Financial Statements for additional information.