Recurring Fair Value Measurements (Details) - USD ($)		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Derivatives, Fair Value [Line Items]
Return Cash Collateral		$ 32,000,000		$ 32,000,000		$ 32,000,000
Reclaim Cash Collateral		4,000,000		4,000,000		11,000,000
Commodity Trading
Changes in Level 3 Commodity Derivatives [Roll Forward]
Balance at beginning of period		4,000,000	$ (7,000,000)	4,000,000	$ 29,000,000
Purchases		37,000,000	34,000,000	49,000,000	38,000,000
Settlements		(25,000,000)	(16,000,000)	(42,000,000)	(27,000,000)
Gains (losses) recognized in earnings	[1]	9,000,000	7,000,000	14,000,000	(11,000,000)
Net gains (losses) recognized as regulatory assets and liabilities		9,000,000	10,000,000	9,000,000	(1,000,000)
Balance at end of period		34,000,000	28,000,000	34,000,000	28,000,000
Transfers Level 3, Net		0	$ 0	0	$ 0
Other Current Assets
Derivatives, Fair Value [Line Items]
Derivative Asset, Net		72,000,000		72,000,000		55,000,000
Other Noncurrent Assets
Derivatives, Fair Value [Line Items]
Derivative Asset, Net		38,000,000		38,000,000		22,000,000
Other Current Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liability, Net		40,000,000		40,000,000		38,000,000
Other Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liability, Net		181,000,000		181,000,000		175,000,000
Fair Value Measured on a Recurring Basis | Other Current Assets
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		121,000,000		121,000,000		105,000,000
Netting	[2]	(52,000,000)		(52,000,000)		(53,000,000)
Derivative Asset, Net		69,000,000		69,000,000		52,000,000
Fair Value Measured on a Recurring Basis | Other Current Assets | Level 1
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		5,000,000		5,000,000		3,000,000
Fair Value Measured on a Recurring Basis | Other Current Assets | Level 2
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		59,000,000		59,000,000		57,000,000
Fair Value Measured on a Recurring Basis | Other Current Assets | Level 3
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		57,000,000		57,000,000		45,000,000
Fair Value Measured on a Recurring Basis | Other Current Assets | Other Derivative Instruments | Commodity Trading
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		68,000,000		68,000,000		78,000,000
Netting	[2]	(50,000,000)		(50,000,000)		(52,000,000)
Derivative Asset, Net		18,000,000		18,000,000		26,000,000
Fair Value Measured on a Recurring Basis | Other Current Assets | Other Derivative Instruments | Electric Commodity
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		46,000,000		46,000,000		21,000,000
Netting	[2]	(2,000,000)		(2,000,000)		(1,000,000)
Derivative Asset, Net		44,000,000		44,000,000		20,000,000
Fair Value Measured on a Recurring Basis | Other Current Assets | Other Derivative Instruments | Natural Gas Commodity
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		7,000,000		7,000,000		6,000,000
Netting	[2]	0		0		0
Derivative Asset, Net		7,000,000		7,000,000		6,000,000
Fair Value Measured on a Recurring Basis | Other Current Assets | Other Derivative Instruments | Level 1 | Commodity Trading
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		5,000,000		5,000,000		3,000,000
Fair Value Measured on a Recurring Basis | Other Current Assets | Other Derivative Instruments | Level 1 | Electric Commodity
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		0		0		0
Fair Value Measured on a Recurring Basis | Other Current Assets | Other Derivative Instruments | Level 1 | Natural Gas Commodity
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		0		0		0
Fair Value Measured on a Recurring Basis | Other Current Assets | Other Derivative Instruments | Level 2 | Commodity Trading
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		52,000,000		52,000,000		51,000,000
Fair Value Measured on a Recurring Basis | Other Current Assets | Other Derivative Instruments | Level 2 | Electric Commodity
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		0		0		0
Fair Value Measured on a Recurring Basis | Other Current Assets | Other Derivative Instruments | Level 2 | Natural Gas Commodity
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		7,000,000		7,000,000		6,000,000
Fair Value Measured on a Recurring Basis | Other Current Assets | Other Derivative Instruments | Level 3 | Commodity Trading
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		11,000,000		11,000,000		24,000,000
Fair Value Measured on a Recurring Basis | Other Current Assets | Other Derivative Instruments | Level 3 | Electric Commodity
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		46,000,000		46,000,000		21,000,000
Fair Value Measured on a Recurring Basis | Other Current Assets | Other Derivative Instruments | Level 3 | Natural Gas Commodity
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		0		0		0
Fair Value Measured on a Recurring Basis | Other Noncurrent Assets
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		76,000,000		76,000,000		54,000,000
Netting	[2]	(49,000,000)		(49,000,000)		(45,000,000)
Derivative Asset, Net		27,000,000		27,000,000		9,000,000
Fair Value Measured on a Recurring Basis | Other Noncurrent Assets | Level 1
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		11,000,000		11,000,000		9,000,000
Fair Value Measured on a Recurring Basis | Other Noncurrent Assets | Level 2
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		42,000,000		42,000,000		38,000,000
Fair Value Measured on a Recurring Basis | Other Noncurrent Assets | Level 3
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		23,000,000		23,000,000		7,000,000
Fair Value Measured on a Recurring Basis | Other Noncurrent Assets | Other Derivative Instruments | Commodity Trading
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		76,000,000		76,000,000		54,000,000
Netting	[2]	(49,000,000)		(49,000,000)		(45,000,000)
Derivative Asset, Net		27,000,000		27,000,000		9,000,000
Fair Value Measured on a Recurring Basis | Other Noncurrent Assets | Other Derivative Instruments | Level 1 | Commodity Trading
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		11,000,000		11,000,000		9,000,000
Fair Value Measured on a Recurring Basis | Other Noncurrent Assets | Other Derivative Instruments | Level 2 | Commodity Trading
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		42,000,000		42,000,000		38,000,000
Fair Value Measured on a Recurring Basis | Other Noncurrent Assets | Other Derivative Instruments | Level 3 | Commodity Trading
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		23,000,000		23,000,000		7,000,000
Fair Value Measured on a Recurring Basis | Other Current Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		75,000,000		75,000,000		84,000,000
Netting	[2]	(52,000,000)		(52,000,000)		(64,000,000)
Derivative Liability, Net		23,000,000		23,000,000		20,000,000
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Level 1
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		6,000,000		6,000,000		4,000,000
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Level 2
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		59,000,000		59,000,000		64,000,000
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Level 3
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		10,000,000		10,000,000		16,000,000
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Other Derivative Instruments | Commodity Trading
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		68,000,000		68,000,000		78,000,000
Netting	[2]	(50,000,000)		(50,000,000)		(63,000,000)
Derivative Liability, Net		18,000,000		18,000,000		15,000,000
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Other Derivative Instruments | Electric Commodity
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		2,000,000		2,000,000		1,000,000
Netting	[2]	(2,000,000)		(2,000,000)		(1,000,000)
Derivative Liability, Net		0		0		0
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Other Derivative Instruments | Natural Gas Commodity
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		5,000,000		5,000,000		5,000,000
Netting	[2]	0		0		0
Derivative Liability, Net		5,000,000		5,000,000		5,000,000
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Other Derivative Instruments | Level 1 | Commodity Trading
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		6,000,000		6,000,000		4,000,000
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Other Derivative Instruments | Level 1 | Electric Commodity
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		0		0		0
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Other Derivative Instruments | Level 1 | Natural Gas Commodity
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		0		0		0
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Other Derivative Instruments | Level 2 | Commodity Trading
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		54,000,000		54,000,000		59,000,000
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Other Derivative Instruments | Level 2 | Electric Commodity
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		0		0		0
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Other Derivative Instruments | Level 2 | Natural Gas Commodity
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		5,000,000		5,000,000		5,000,000
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Other Derivative Instruments | Level 3 | Commodity Trading
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		8,000,000		8,000,000		15,000,000
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Other Derivative Instruments | Level 3 | Electric Commodity
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		2,000,000		2,000,000		1,000,000
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Other Derivative Instruments | Level 3 | Natural Gas Commodity
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		0		0		0
Fair Value Measured on a Recurring Basis | Other Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		135,000,000		135,000,000		113,000,000
Netting	[2]	(20,000,000)		(20,000,000)		(13,000,000)
Derivative Liability, Net		115,000,000		115,000,000		100,000,000
Fair Value Measured on a Recurring Basis | Other Noncurrent Liabilities | Level 1
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		4,000,000		4,000,000		2,000,000
Fair Value Measured on a Recurring Basis | Other Noncurrent Liabilities | Level 2
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		95,000,000		95,000,000		79,000,000
Fair Value Measured on a Recurring Basis | Other Noncurrent Liabilities | Level 3
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		36,000,000		36,000,000		32,000,000
Fair Value Measured on a Recurring Basis | Other Noncurrent Liabilities | Other Derivative Instruments | Commodity Trading
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		135,000,000		135,000,000		113,000,000
Netting	[2]	(20,000,000)		(20,000,000)		(13,000,000)
Derivative Liability, Net		115,000,000		115,000,000		100,000,000
Fair Value Measured on a Recurring Basis | Other Noncurrent Liabilities | Other Derivative Instruments | Level 1 | Commodity Trading
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		4,000,000		4,000,000		2,000,000
Fair Value Measured on a Recurring Basis | Other Noncurrent Liabilities | Other Derivative Instruments | Level 2 | Commodity Trading
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		95,000,000		95,000,000		79,000,000
Fair Value Measured on a Recurring Basis | Other Noncurrent Liabilities | Other Derivative Instruments | Level 3 | Commodity Trading
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		36,000,000		36,000,000		32,000,000
Fair Value, Measurements, Nonrecurring | Other Current Assets | PPAs
Derivatives, Fair Value [Line Items]
Derivative Asset, Net	[3]	3,000,000		3,000,000		3,000,000
Fair Value, Measurements, Nonrecurring | Other Noncurrent Assets | PPAs
Derivatives, Fair Value [Line Items]
Derivative Asset, Net	[3]	11,000,000		11,000,000		13,000,000
Fair Value, Measurements, Nonrecurring | Other Current Liabilities | PPAs
Derivatives, Fair Value [Line Items]
Derivative Liability, Net	[3]	17,000,000		17,000,000		18,000,000
Fair Value, Measurements, Nonrecurring | Other Noncurrent Liabilities | PPAs
Derivatives, Fair Value [Line Items]
Derivative Liability, Net	[3]	$ 66,000,000		$ 66,000,000		$ 75,000,000

[1] Amounts relate to commodity derivatives held at the end of the period.

[2] Xcel Energy nets derivative instruments and related collateral in its consolidated balance sheet when supported by a legally enforceable master netting agreement, and all derivative instruments and related collateral amounts were subject to master netting agreements at June 30, 2020 and Dec. 31, 2019. At both June 30, 2020 and Dec. 31, 2019, derivative assets and liabilities include $32 million of obligations to return cash collateral and rights to reclaim cash collateral of $4 million and $11 million, respectively. Counterparty netting amounts presented exclude settlement receivables and payables and non-derivative amounts that may be subject to the same master netting agreements.

[3] During 2006, Xcel Energy qualified these contracts under the normal purchase exception. Based on this qualification, contracts are no longer adjusted to fair value and the previous carrying value of these contracts is being amortized over the remaining contract lives along with the offsetting regulatory assets and liabilities.