Benefit Plans - Cash flows (Narrative) (Details) - USD ($)	1 Months Ended	12 Months Ended
	Oct. 31, 2024	Dec. 31, 2024	Dec. 31, 2023
Pension benefits
Components of net periodic cost
Discretionary contribution to qualified pension plan	$ 35,000,000
Defined benefit pension plans, estimated employer contributions in next fiscal year		$ 16,000,000
Employer contribution		45,000,000	$ 14,000,000
Postretirement benefits
Components of net periodic cost
Defined benefit pension plans, estimated employer contributions in next fiscal year		0
Employer contribution		24,000,000	26,000,000
Participant contributions		$ 13,000,000	$ 16,000,000