Employee Benefit Plans - MEC - Employer Contributions (Details) $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($)
Other Postretirement Plans
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, expected contributions in current fiscal year	$ 5
Employer contributions	1
MEC | Other Postretirement Plans
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, expected contributions in current fiscal year	2
Employer contributions	1
U.S. | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, expected contributions in current fiscal year	13
Employer contributions	3
U.S. | MEC | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, expected contributions in current fiscal year	8
Employer contributions	$ 2