Schedule III Supplementary Insurance Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Supplementary Insurance Information, by Segment [Line Items]
Deferred Policy Acquisition Costs	$ 9,805	$ 11,207
Liability for Unpaid Losses and Loss Adjustment Expenses, Future Policy Benefits	128,817	128,840
Unearned Premiums	18,660	18,269
Policy and Contract Claims	1,378	993
Premiums and Policy Fees	31,440	33,576	$ 33,405
Net Investment Income	13,631	14,619	13,086
Losses and Loss Expenses Incurred, Benefits	28,428	29,234	31,166
Amortization of Deferred Policy Acquisition Costs	4,211	5,164	5,386
Other Operating Expenses	8,396	8,537	9,302
Net Premiums Written	23,456	25,454	26,797
General Insurance
Supplementary Insurance Information, by Segment [Line Items]
Deferred Policy Acquisition Costs	2,489	2,632
Liability for Unpaid Losses and Loss Adjustment Expenses, Future Policy Benefits	74,315	74,821
Unearned Premiums	18,595	18,237
Policy and Contract Claims	0	0
Premiums and Policy Fees	23,662	26,438	27,505
Net Investment Income	2,925	3,444	2,843
Losses and Loss Expenses Incurred, Benefits	16,803	17,246	20,824
Amortization of Deferred Policy Acquisition Costs	3,538	4,482	4,596
Other Operating Expenses	4,345	4,621	5,222
Net Premiums Written	22,959	25,092	26,407
Life and Retirement
Supplementary Insurance Information, by Segment [Line Items]
Deferred Policy Acquisition Costs	7,316	8,575
Liability for Unpaid Losses and Loss Adjustment Expenses, Future Policy Benefits	48,864	48,388
Unearned Premiums	57	0
Policy and Contract Claims	1,336	963
Premiums and Policy Fees	7,498	6,712	5,489
Net Investment Income	8,881	8,733	8,238
Losses and Loss Expenses Incurred, Benefits	10,435	9,427	7,993
Amortization of Deferred Policy Acquisition Costs	632	672	700
Other Operating Expenses	2,522	2,542	2,478
Net Premiums Written	0	0	0
Other Operations
Supplementary Insurance Information, by Segment [Line Items]
Deferred Policy Acquisition Costs	0	0
Liability for Unpaid Losses and Loss Adjustment Expenses, Future Policy Benefits	5,638	5,631
Unearned Premiums	8	32
Policy and Contract Claims	42	30
Premiums and Policy Fees	280	426	411
Net Investment Income	1,825	2,442	2,005
Losses and Loss Expenses Incurred, Benefits	1,190	2,561	2,349
Amortization of Deferred Policy Acquisition Costs	41	10	90
Other Operating Expenses	1,529	1,374	1,602
Net Premiums Written	$ 497	$ 362	$ 390