Recurring Fair Value Measurements (Details) - USD ($)		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Derivatives, Fair Value [Line Items]
Return Cash Collateral		$ 32,000,000		$ 32,000,000
Reclaim Cash Collateral		6,000,000		11,000,000
Commodity Trading
Changes in Level 3 Commodity Derivatives [Roll Forward]
Balance at beginning of period		4,000,000	$ 29,000,000
Purchases		12,000,000	4,000,000
Settlements		(18,000,000)	(11,000,000)
Gains (losses) recognized in earnings	[1]	6,000,000	(18,000,000)
Net gains (losses) recognized as regulatory assets and liabilities		1,000,000	(11,000,000)
Balance at end of period		5,000,000	(7,000,000)
Transfers Level 3, Net		0	$ 0
Other Current Assets
Derivatives, Fair Value [Line Items]
Derivative Asset, Net		45,000,000		55,000,000
Other Noncurrent Assets
Derivatives, Fair Value [Line Items]
Derivative Asset, Net		39,000,000		22,000,000
Other Current Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liability, Net		52,000,000		38,000,000
Other Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liability, Net		183,000,000		175,000,000
Fair Value Measured on a Recurring Basis | Other Current Assets
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		105,000,000		105,000,000
Netting	[2]	(63,000,000)		(53,000,000)
Derivative Asset, Net		42,000,000		52,000,000
Fair Value Measured on a Recurring Basis | Other Current Assets | Level 1
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		8,000,000		3,000,000
Fair Value Measured on a Recurring Basis | Other Current Assets | Level 2
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		63,000,000		57,000,000
Fair Value Measured on a Recurring Basis | Other Current Assets | Level 3
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		34,000,000		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		87,000,000		78,000,000
Netting	[2]	(63,000,000)		(52,000,000)
Derivative Asset, Net		24,000,000		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		18,000,000		21,000,000
Netting	[2]	0		(1,000,000)
Derivative Asset, Net		18,000,000		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		0		6,000,000
Netting	[2]	0		0
Derivative Asset, Net		0		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		8,000,000		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
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
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		63,000,000		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
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		0		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		16,000,000		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		18,000,000		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
Fair Value Measured on a Recurring Basis | Other Noncurrent Assets
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		72,000,000		54,000,000
Netting	[2]	(45,000,000)		(45,000,000)
Derivative Asset, Net		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		10,000,000		9,000,000
Fair Value Measured on a Recurring Basis | Other Noncurrent Assets | Level 2
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		38,000,000		38,000,000
Fair Value Measured on a Recurring Basis | Other Noncurrent Assets | Level 3
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		24,000,000		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		70,000,000		54,000,000
Netting	[2]	(45,000,000)		(45,000,000)
Derivative Asset, Net		25,000,000		9,000,000
Fair Value Measured on a Recurring Basis | Other Noncurrent Assets | Other Derivative Instruments | Electric Commodity
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		2,000,000		0
Netting	[2]	0		0
Derivative Asset, Net		2,000,000		0
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		10,000,000		9,000,000
Fair Value Measured on a Recurring Basis | Other Noncurrent Assets | Other Derivative Instruments | Level 1 | Electric Commodity
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		0		0
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		38,000,000		38,000,000
Fair Value Measured on a Recurring Basis | Other Noncurrent Assets | Other Derivative Instruments | Level 2 | Electric Commodity
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		0		0
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		22,000,000		7,000,000
Fair Value Measured on a Recurring Basis | Other Noncurrent Assets | Other Derivative Instruments | Level 3 | Electric Commodity
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		2,000,000		0
Fair Value Measured on a Recurring Basis | Other Current Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		97,000,000		84,000,000
Netting	[2]	(63,000,000)		(64,000,000)
Derivative Liability, Net		34,000,000		20,000,000
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Level 1
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		8,000,000		4,000,000
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Level 2
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		75,000,000		64,000,000
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Level 3
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		14,000,000		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		84,000,000		78,000,000
Netting	[2]	(63,000,000)		(63,000,000)
Derivative Liability, Net		21,000,000		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		0		1,000,000
Netting	[2]	0		(1,000,000)
Derivative Liability, Net		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		0		5,000,000
Netting	[2]	0		0
Derivative Liability, Net		0		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		8,000,000		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
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
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		62,000,000		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
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		0		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		14,000,000		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		0		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
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Designated as Hedging Instrument | Interest Rate Swap
Derivatives, Fair Value [Line Items]
Netting	[2]	0		0
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Designated as Hedging Instrument | Cash Flow Hedges | Interest Rate Swap
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		13,000,000		0
Derivative Liability, Net		13,000,000		0
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Designated as Hedging Instrument | Level 1 | Cash Flow Hedges | Interest Rate Swap
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		0		0
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Designated as Hedging Instrument | Level 2 | Cash Flow Hedges | Interest Rate Swap
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		13,000,000		0
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Designated as Hedging Instrument | Level 3 | Cash Flow Hedges | Interest Rate Swap
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		0		0
Fair Value Measured on a Recurring Basis | Other Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		131,000,000		113,000,000
Netting	[2]	(19,000,000)		(13,000,000)
Derivative Liability, Net		112,000,000		100,000,000
Fair Value Measured on a Recurring Basis | Other Noncurrent Liabilities | Level 1
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		3,000,000		2,000,000
Fair Value Measured on a Recurring Basis | Other Noncurrent Liabilities | Level 2
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		89,000,000		79,000,000
Fair Value Measured on a Recurring Basis | Other Noncurrent Liabilities | Level 3
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		39,000,000		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		131,000,000		113,000,000
Netting	[2]	(19,000,000)		(13,000,000)
Derivative Liability, Net		112,000,000		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		3,000,000		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		89,000,000		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		39,000,000		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
Fair Value, Measurements, Nonrecurring | Other Noncurrent Assets | PPAs
Derivatives, Fair Value [Line Items]
Derivative Asset, Net	[3]	12,000,000		13,000,000
Fair Value, Measurements, Nonrecurring | Other Current Liabilities | PPAs
Derivatives, Fair Value [Line Items]
Derivative Liability, Net	[3]	18,000,000		18,000,000
Fair Value, Measurements, Nonrecurring | Other Noncurrent Liabilities | PPAs
Derivatives, Fair Value [Line Items]
Derivative Liability, Net	[3]	$ 71,000,000		$ 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 March 31, 2020 and Dec. 31, 2019. At both March 31, 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 $6 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.