Pension and Postretirement Benefit Plans - Narrative (Details) $ in Millions	3 Months Ended
	Mar. 31, 2022 USD ($)
Qualified and Non-qualified Pension Benefits
Benefit Plan Information
Company contributions year to date	$ 41
Postretirement Benefits
Benefit Plan Information
Company contributions year to date	1
Pension and Postretirement Benefit Plans | Minimum
Benefit Plan Information
Estimated pension and postretirement employer contributions in current fiscal year	100
Pension and Postretirement Benefit Plans | Maximum
Benefit Plan Information
Estimated pension and postretirement employer contributions in current fiscal year	$ 200