Other Revenues and Other Expenses Other Revenues (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 724	$ 604	$ 1,458	$ 1,215
Other revenues	845	679	1,697	1,366
Equity Method Investee
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	11	12	22	24
Reclassification, Segmentation Basis Change \| MIM
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		24		49
Vision fee for service arrangements
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	144	133	303	287
Prepaid legal plans
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	176	158	352	319
Institutional Client asset management fees (1)
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	186	95	372	172
Administrative services-only contracts
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	82	73	163	147
Recordkeeping and administrative services (2)
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	35	34	69	70
Other revenue related to service contracts from customers (1) (3)
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	101	111	199	220
Financial Service, Other
Disaggregation of Revenue [Line Items]
Other revenues	$ 121	$ 75	$ 239	$ 151