Other Revenues and Other Expenses Other Revenues (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 577	$ 562
Other revenues	674	639
Vision fee for service arrangements
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	146	159
Prepaid legal plans
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	148	131
Fee-based investment management
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	98	100
Administrative services-only contracts
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	67	64
Recordkeeping and administrative services (1)
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	38	37
Other revenue from service contracts from customers
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	80	71
Other Income
Disaggregation of Revenue [Line Items]
Other revenues	$ 97	$ 77