CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Revenues
Net premiums	$ 4,255.0	$ 3,247.0	$ 10,977.0	$ 9,632.0
Net investment income	922.0	769.0	2,635.0	2,333.0
Investment related gains (losses), net	(126.0)	(154.0)	(326.0)	(533.0)
Other revenues	102.0	188.0	274.0	438.0
Total revenues	5,153.0	4,050.0	13,560.0	11,870.0
Benefits and expenses
Claims and other policy benefits	3,959.0	3,048.0	10,035.0	8,857.0
Liability for Future Policy Benefit, Remeasurement Gain (Loss)	(82.0)	226.0	(95.0)	302.0
Market Risk Benefit, Change in Fair Value, Gain (Loss)	(21.0)	23.0	(38.0)	29.0
Interest credited	223.0	189.0	647.0	468.0
Policy acquisition costs and other insurance expenses	348.0	341.0	1,028.0	1,021.0
Other operating expenses	274.0	251.0	799.0	720.0
Interest expense	72.0	49.0	188.0	136.0
Total benefits and expenses	4,773.0	4,127.0	12,564.0	11,533.0
Income before income taxes	380.0	(77.0)	996.0	337.0
Provision for income taxes	91.0	(2.0)	247.0	109.0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	289.0	(75.0)	749.0	228.0	$ 521.0
Net Income (Loss) Attributable to Noncontrolling Interest	2.0	1.0	5.0	2.0	4.0
Net income (loss)	$ 287.0	$ (76.0)	$ 744.0	$ 226.0	$ 517.0	$ 1,170.0
Earnings per share
Basic earnings per share	$ 4.34	$ (1.13)	$ 11.19	$ 3.38
Diluted earnings per share	$ 4.29	$ (1.13)	$ 11.06	$ 3.35