Segment Information (Premiums, Fees and Other Revenues by US and Foreign Operations) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Premiums, Fees & Other Revenues	$ 50,384	$ 49,486	$ 49,680
UNITED STATES
Segment Reporting Information [Line Items]
Premiums, Fees & Other Revenues	35,252	34,717	34,433
Japan
Segment Reporting Information [Line Items]
Premiums, Fees & Other Revenues	6,426	6,750	6,608
Other Foreign
Segment Reporting Information [Line Items]
Premiums, Fees & Other Revenues	$ 8,706	$ 8,019	$ 8,639