Employee Benefits - Derivative Instruments (Details) - Combined Pension Plan - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Exchange-traded U.S. equity futures
Defined Benefit Plan Disclosure [Line Items]
Derivative, notional amount	$ 212	$ 60
Exchange-traded Treasury and other interest rate futures
Defined Benefit Plan Disclosure [Line Items]
Derivative, notional amount	795	1,136
Exchange-traded Foreign currency futures
Defined Benefit Plan Disclosure [Line Items]
Derivative, notional amount	0	1
Interest rate swaps
Defined Benefit Plan Disclosure [Line Items]
Derivative, notional amount	149	214
Credit default swaps
Defined Benefit Plan Disclosure [Line Items]
Derivative, notional amount	124	72
Index swaps
Defined Benefit Plan Disclosure [Line Items]
Derivative, notional amount	701	94
Foreign exchange forwards
Defined Benefit Plan Disclosure [Line Items]
Derivative, notional amount	47	57
Options
Defined Benefit Plan Disclosure [Line Items]
Derivative, notional amount	$ 15	$ 32