Other Revenues and Other Expenses Other Revenues (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 604	$ 558	$ 1,215	$ 1,135
Other revenues	679	638	1,366	1,312
Vision fee for service arrangements
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	133	130	287	276
Prepaid legal plans
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	158	145	319	293
Fee-based investment management
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	119	98	221	196
Administrative services-only contracts
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	73	69	147	136
Recordkeeping and administrative services (1)
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	34	37	70	75
Other revenue from service contracts from customers
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	87	79	171	159
Other Income
Disaggregation of Revenue [Line Items]
Other revenues	$ 75	$ 80	$ 151	$ 177