Schedule II (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2022		Dec. 31, 2021		Dec. 31, 2020
Allowance for Bad Debts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Jan. 1		$ 106		$ 79		$ 55
Charged to costs and expenses		73		60		60
Charged to other accounts	[1]	26		14		12
Deductions from reserves	[2]	83		47		48
Balance at Dec. 31		122		106		79
NOL and Tax Credit Valuation Allowances
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Jan. 1		64		64		67
Charged to costs and expenses		6		5		6
Charged to other accounts		0		0		0
Deductions from reserves		8	[3]	5	[3]	9	[4]
Balance at Dec. 31		$ 62		$ 64		$ 64

[1] Recovery of amounts previously written-off.

[2] Deductions related primarily to bad debt write-offs.

[3] Primarily reductions to valuation allowances due to additional NOLs and tax credits forecasted to be used prior to expiration.

[4] Primarily the reduction of valuation allowances for North Dakota ITC, net of federal income tax benefit, that is offset to a regulatory liability forecasted to be used prior to expiration along with valuation allowances that expired.