Employee Benefits, Weighted-Average Assumptions Used to Determine Net Periodic Benefit Cost (Details)		3 Months Ended												12 Months Ended
		Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension Plan
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate (percent)	[1]	2.30%	1.95%	2.05%	2.05%	1.70%	1.85%	2.20%	2.95%	2.70%	2.60%	3.25%	3.80%
Expected return on plan assets (percent)														6.50%	7.00%	7.00%
Rate of compensation increase (percent)														3.00%	3.00%	3.86%
SRP
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate (percent)														1.55%	2.70%	4.10%
Expected return on plan assets (percent)														6.50%	7.00%	7.00%
Rate of compensation increase (percent)														3.00%	3.00%	3.86%
PBOP
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate (percent)														2.60%	3.30%	4.30%
Expected return on plan assets (percent)														2.81%	3.61%	3.61%

[1] Pension expense was remeasured quarterly in 2021, 2020 and 2019. The quarterly remeasurements for each quarter in 2021, 2020 and 2019 were as follows: Quarter 1: 2.05%, 2.95% and 3.80%; Quarter 2: 2.05%, 2.20% and 3.25%; Quarter 3: 1.95%, 1.85% and 2.60%; and Quarter 4: 2.30%, 1.70% and 2.70%.