Insurance (Rollforward of Unpaid Claims) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Liability for Claims and Claims Adjustment Expense [Line Items]
Balance at January 1,	$ 18,591	$ 19,216	$ 17,788
Less: Reinsurance recoverables	2,417	2,377	2,332
Net Balance at January 1,	16,174	16,839	15,456
Incurred related to:
Current year	28,270	27,272	27,093
Prior years	934	192	313
Total incurred	29,204	27,464	27,406
Paid related to:
Current year	(21,111)	(20,230)	(20,141)
Prior years	(7,256)	(6,241)	(5,882)
Total paid	(28,367)	(26,471)	(26,023)
Liability for Unpaid Claims and Claims Adjustment Expense, Adjustments	14,501
Net Balance at December 31,	16,892	16,174	16,839
Add: Reinsurance recoverables	3,121	2,417	2,377
Balance at December 31,	20,013	18,591	19,216
Disposal Group, Held-for-sale, Not Discontinued Operations
Paid related to:
Liability for Unpaid Claims and Claims Adjustment Expense, Adjustments	(55)	(1,658)	0
Disposal Group, Disposed of by Sale, Not Discontinued Operations
Paid related to:
Liability for Unpaid Claims and Claims Adjustment Expense, Adjustments	$ (64)	$ 0	$ 0