Short-Term Debt (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Short-term Debt [Line Items]
Short-term Debt	$ 0	$ 0	$ 179
Money Pool [Member]
Short-term Debt [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	250	250	250	$ 250
Short-term Debt	0	0	0	0
Short-term Debt, Average Outstanding Amount	0	6	3	32
Short-term Debt, Maximum Amount Outstanding During Period	0	$ 236	$ 116	$ 250
Line of Credit Facility, Interest Rate During Period		0.07%	1.53%	2.05%
Commercial Paper [Member]
Short-term Debt [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	500	$ 500	$ 500	$ 500
Short-term Debt	0	0	179	30
Short-term Debt, Average Outstanding Amount	0	26	10	71
Short-term Debt, Maximum Amount Outstanding During Period	$ 13	$ 317	$ 179	$ 317
Short-term Debt, Weighted Average Interest Rate, at Point in Time			0.18%	2.05%
Line of Credit Facility, Interest Rate During Period	0.15%	0.18%	1.25%	2.59%