Retirement Plans (Fair Value, Investments, Entities That Calculate Net Asset Value Per Share) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024		Dec. 31, 2023
Defined Benefit Plan Disclosure [Line Items]
Fair value, investments, entities that calculate net Asset value per share, unfunded commitments	$ 222		$ 278
Investments, fair value disclosure	2,436		2,689
Hedge funds
Defined Benefit Plan Disclosure [Line Items]
Fair value, investments, entities that calculate net Asset value per share, unfunded commitments	$ 93		$ 103
Fair value, investments, entities that calculate net asset value per share, investment redemption, frequency	Quarterly to semi-annually		Quarterly to semi-annually
Fair value, investments, entities that calculate net asset value per share, investment redemption, description	45 - 60 days		45 - 60 days
Defined benefit plan, plan assets, amount	$ 1,148		$ 1,293
Private equity
Defined Benefit Plan Disclosure [Line Items]
Fair value, investments, entities that calculate net Asset value per share, unfunded commitments	$ 50		$ 81
Fair value, investments, entities that calculate net asset value per share, investment redemption, frequency	(a)	[1]	(a)	[2]
Fair value, investments, entities that calculate net asset value per share, investment redemption, description	None		None
Defined benefit plan, plan assets, amount	$ 599		$ 644
Real estate funds
Defined Benefit Plan Disclosure [Line Items]
Fair value, investments, entities that calculate net Asset value per share, unfunded commitments	$ 79		$ 94
Fair value, investments, entities that calculate net asset value per share, investment redemption, frequency	Quarterly		Quarterly
Fair value, investments, entities that calculate net asset value per share, investment redemption, description	45 - 60 days		45 - 60 days
Defined benefit plan, plan assets, amount	$ 689		$ 752

[1] A private equity fund investment ("partnership interest") is contractually locked up for the life of the private equity fund by the partnership agreement. Limited partners do not have the option to redeem partnership interests.

[2] A private equity fund investment ("partnership interest") is contractually locked up for the life of the private equity fund by the partnership agreement. Limited partners do not have the option to redeem partnership interests.