Accounting Changes and Error Corrections (Income Statement) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022	Dec. 31, 2021
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net premiums	$ 3,385.0	$ 3,155.0
Net investment income	856.0	810.0
Total investment related gains (losses), net	(77.0)	(139.0)
Other revenues	87.0	91.0
Revenues	4,251.0	3,917.0
Claims and other policy benefits	3,063.0	2,871.0
Liability for Future Policy Benefit, Remeasurement Gain (Loss)	(26.0)	58.0
Market Risk Benefit, Change in Fair Value, Gain (Loss)	14.0	(34.0)
Interest credited	215.0	141.0
Policy acquisition costs and other insurance expenses	331.0	344.0
Other operating expenses	250.0	227.0
Interest expense	50.0	42.0
Collateral finance and securitization expense	3.0	1.0
Benefits, Losses and Expenses	3,900.0	3,650.0
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	351.0	267.0
Provision for income taxes	98.0	70.0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	253.0	197.0	$ 521.0
Net Income (Loss) Attributable to Noncontrolling Interest	1.0	0.0	4.0
Net income	$ 252.0	$ 197.0	517.0	$ 1,170.0
Accounting Standards Update 2018-12
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net premiums			13,078.0	12,513.0
Net investment income			3,161.0	3,138.0
Total investment related gains (losses), net			(539.0)	567.0
Other revenues			527.0	449.0
Revenues			16,227.0	16,667.0
Claims and other policy benefits			11,982.0	11,673.0
Liability for Future Policy Benefit, Remeasurement Gain (Loss)			291.0	567.0
Market Risk Benefit, Change in Fair Value, Gain (Loss)			10.0	(58.0)
Interest credited			682.0	700.0
Policy acquisition costs and other insurance expenses			1,344.0	1,325.0
Other operating expenses			1,009.0	936.0
Interest expense			184.0	127.0
Collateral finance and securitization expense			7.0	12.0
Benefits, Losses and Expenses			15,509.0	15,282.0
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest			718.0	1,385.0
Provision for income taxes			197.0	215.0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest			521.0	1,170.0
Net Income (Loss) Attributable to Noncontrolling Interest			4.0	0.0
Net income			517.0	1,170.0
Accounting Standards Update 2018-12 | Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net premiums			13,078.0	12,513.0
Net investment income			3,161.0	3,138.0
Total investment related gains (losses), net			(506.0)	560.0
Other revenues			525.0	447.0
Revenues			16,258.0	16,658.0
Claims and other policy benefits			12,046.0	12,776.0
Liability for Future Policy Benefit, Remeasurement Gain (Loss)			0.0	0.0
Market Risk Benefit, Change in Fair Value, Gain (Loss)			0.0	0.0
Interest credited			682.0	700.0
Policy acquisition costs and other insurance expenses			1,499.0	1,416.0
Other operating expenses			1,009.0	936.0
Interest expense			184.0	127.0
Collateral finance and securitization expense			7.0	12.0
Benefits, Losses and Expenses			15,427.0	15,967.0
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest			831.0	691.0
Provision for income taxes			204.0	74.0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest			627.0	617.0
Net Income (Loss) Attributable to Noncontrolling Interest			4.0	0.0
Net income			623.0	617.0
Accounting Standards Update 2018-12 | Revision of Prior Period, Change in Accounting Principle, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net premiums			0.0	0.0
Net investment income			0.0	0.0
Total investment related gains (losses), net			(33.0)	7.0
Other revenues			2.0	2.0
Revenues			(31.0)	9.0
Claims and other policy benefits			(64.0)	(1,103.0)
Liability for Future Policy Benefit, Remeasurement Gain (Loss)			291.0	567.0
Market Risk Benefit, Change in Fair Value, Gain (Loss)			10.0	(58.0)
Interest credited			0.0	0.0
Policy acquisition costs and other insurance expenses			(155.0)	(91.0)
Other operating expenses			0.0	0.0
Interest expense			0.0	0.0
Collateral finance and securitization expense			0.0	0.0
Benefits, Losses and Expenses			82.0	(685.0)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest			(113.0)	694.0
Provision for income taxes			(7.0)	141.0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest			(106.0)	553.0
Net Income (Loss) Attributable to Noncontrolling Interest			0.0	0.0
Net income			$ (106.0)	$ 553.0