Segment Information (Premiums, Fees and Other Revenues by US and Foreign Operations) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Premiums, Fees & Other Revenues	$ 52,520	$ 51,961	$ 56,365
UNITED STATES
Segment Reporting Information [Line Items]
Premiums, Fees & Other Revenues	37,266	36,869	42,250
Japan
Segment Reporting Information [Line Items]
Premiums, Fees & Other Revenues	4,702	5,020	5,460
Other Foreign
Segment Reporting Information [Line Items]
Premiums, Fees & Other Revenues	$ 10,552	$ 10,072	$ 8,655