Benefit Plans and Other Postretirement Benefits, Pension Benefits (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2020	Jan. 01, 2019
Target Pension Asset Allocations [Abstract]
annual interest crediting rates		$ 2.24	$ 3.11	$ 3.86
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value		388,000,000	348,000,000
Fair value of plan assets		1,283,000,000	1,124,000,000		$ 1,124,000,000	$ 966,000,000
Pension Benefits [Abstract]
Total benefit obligation		1,428,000,000	1,330,000,000		$ 1,330,000,000	$ 1,229,000,000
Net benefit cost recognized for financial reporting		$ 37,000,000	$ 38,000,000	$ 36,000,000
Minimum number of years historical achieved weighted average annual returns used to determine investment return assumptions (in years)		20 years
Expected average long-term rate of return on assets (as a percent)		6.84%	6.84%	6.84%
Target Pension Asset Allocations [Abstract]
Target pension asset allocations (as a percent)		100.00%	100.00%
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement		$ 0	$ (3,000,000)	$ (5,000,000)
Pension Plan [Member] | PSCo [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets			1,124,000,000
Target Pension Asset Allocations [Abstract]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement			(3,000,000)	$ (5,000,000)
Supplemental Executive Retirement Plan (SERP) and Nonqualified Pension Plan
Pension Benefits [Abstract]
Total benefit obligation		3,000,000
Xcel Energy Inc. | Supplemental Executive Retirement Plan (SERP) and Nonqualified Pension Plan
Pension Benefits [Abstract]
Total benefit obligation		43,000,000	39,000,000
Net benefit cost recognized for financial reporting		6,000,000	4,000,000
Equity Securities [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value		0	0
Fair value of plan assets		$ 27,000,000	$ 30,000,000
Target Pension Asset Allocations [Abstract]
Target pension asset allocations (as a percent)		35.00%	37.00%
Long-Duration Fixed Income and Interest Rate Swap Securities [Member] | Pension Plan [Member]
Target Pension Asset Allocations [Abstract]
Target pension asset allocations (as a percent)		35.00%	30.00%
Short-to-intermediate fixed income securities [Member] | Pension Plan [Member]
Target Pension Asset Allocations [Abstract]
Target pension asset allocations (as a percent)		13.00%	14.00%
Alternative Investments [Member] | Pension Plan [Member]
Target Pension Asset Allocations [Abstract]
Target pension asset allocations (as a percent)		15.00%	17.00%
Cash | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value		$ 0	$ 0
Fair value of plan assets		$ 75,000,000	$ 46,000,000
Target Pension Asset Allocations [Abstract]
Target pension asset allocations (as a percent)		2.00%	2.00%
Subsequent Event | Pension Plan [Member]
Pension Benefits [Abstract]
Expected average long-term rate of return on assets for next fiscal year (as a percent)	6.38%