Schedule IV (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Premiums	$ 31,857	$ 31,259	$ 28,523
Reportable Segments
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct	36,791	34,875	32,977
Ceded Premiums Earned	13,389	12,521	11,496
Assumed	8,455	8,905	7,042
Premiums	$ 31,857	$ 31,259	$ 28,523
Percent of Amount Assumed to Net	26.50%	28.50%	24.70%
Reportable Segments | General Insurance
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct	$ 32,053	$ 30,279	$ 28,596
Ceded Premiums Earned	12,425	11,301	10,435
Assumed	7,137	6,640	5,984
Premiums	$ 26,765	$ 25,618	$ 24,145
Percent of Amount Assumed to Net	26.70%	25.90%	24.80%
Reportable Segments | Life and Retirement
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct	$ 4,738	$ 4,596	$ 4,381
Ceded Premiums Earned	964	1,220	1,061
Assumed	1,318	2,265	1,058
Premiums	$ 5,092	$ 5,641	$ 4,378
Percent of Amount Assumed to Net	25.90%	40.20%	24.20%
Long Duration Insurance
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct	$ 1,280,831	$ 1,280,090	$ 1,243,389
Ceded Premiums Earned	346,879	363,008	349,453
Assumed	188	192	225
Premiums	$ 934,140	$ 917,274	$ 894,161
Percent of Amount Assumed to Net	0.00%	0.00%	0.00%