Fair Value of Financial Assets and Liabilities - Recurring Fair Value Measurements (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Derivatives, Fair Value [Line Items]
Return Cash Collateral		$ 0		$ 0		$ 0
Reclaim Cash Collateral		7		7		46
Other Derivative Instruments
Derivatives, Fair Value [Line Items]
Pre-tax (gains) losses reclassified into income during the period from regulatory assets and (liabilities)		0	$ 0	(10)	$ 2
Other Derivative Instruments | Natural Gas Commodity
Derivatives, Fair Value [Line Items]
Pre-tax (gains) losses reclassified into income during the period from regulatory assets and (liabilities)	[1]			(10)	$ 2
Fair Value Measured on a Recurring Basis | Other Derivative Instruments | Natural Gas Commodity
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		2		2		12
Netting	[2]	0		0		0
Derivative Asset, Net		2		2		12
Derivative Liability, Gross		0		0		10
Netting	[2]	0		0		0
Derivative Liability, Net		0		0		10
Fair Value Measured on a Recurring Basis | Other Derivative Instruments | Level 1 | Natural Gas Commodity
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		0		0		0
Derivative Liability, Gross		0		0		0
Fair Value Measured on a Recurring Basis | Other Derivative Instruments | Level 2 | Natural Gas Commodity
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		2		2		12
Derivative Liability, Gross		0		0		10
Fair Value Measured on a Recurring Basis | Other Derivative Instruments | Level 3 | Natural Gas Commodity
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		0		0		0
Derivative Liability, Gross		0		0		0
Fair Value Measured on a Recurring Basis | Other Current Assets
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		50		50		249
Netting	[2]	(37)		(37)		(184)
Derivative Asset, Net		13		13		65
Fair Value Measured on a Recurring Basis | Other Current Assets | Level 1
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		3		3		16
Fair Value Measured on a Recurring Basis | Other Current Assets | Level 2
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		44		44		232
Fair Value Measured on a Recurring Basis | Other Current Assets | Level 3
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		3		3		1
Fair Value Measured on a Recurring Basis | Other Current Assets | Other Derivative Instruments | Commodity Trading
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		48		48		237
Netting	[2]	(37)		(37)		(184)
Derivative Asset, Net		11		11		53
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		3		3		16
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		42		42		220
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		3		3		1
Fair Value Measured on a Recurring Basis | Other Noncurrent Assets
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		18		18		53
Netting	[2]	(5)		(5)		(31)
Derivative Asset, Net		13		13		22
Fair Value Measured on a Recurring Basis | Other Noncurrent Assets | Level 1
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		8		8		12
Fair Value Measured on a Recurring Basis | Other Noncurrent Assets | Level 2
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		2		2		32
Fair Value Measured on a Recurring Basis | Other Noncurrent Assets | Level 3
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		8		8		9
Fair Value Measured on a Recurring Basis | Other Noncurrent Assets | Other Derivative Instruments | Commodity Trading
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		18		18		53
Netting	[2]	(5)		(5)		(31)
Derivative Asset, Net		13		13		22
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		8		8		12
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		2		2		32
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		8		8		9
Fair Value Measured on a Recurring Basis | Other Current Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		52		52		253
Netting	[2]	(43)		(43)		(223)
Derivative Liability, Net		9		9		30
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Level 1
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		1		1		5
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Level 2
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		51		51		247
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Level 3
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		0		0		1
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Other Derivative Instruments | Commodity Trading
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		52		52		243
Netting	[2]	(43)		(43)		(223)
Derivative Liability, Net		9		9		20
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		1		1		5
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		51		51		237
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		0		0		1
Fair Value Measured on a Recurring Basis | Other Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		8		8		47
Netting	[2]	(6)		(6)		(38)
Derivative Liability, Net		2		2		9
Fair Value Measured on a Recurring Basis | Other Noncurrent Liabilities | Level 1
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		4		4		7
Fair Value Measured on a Recurring Basis | Other Noncurrent Liabilities | Level 2
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		4		4		40
Fair Value Measured on a Recurring Basis | Other Noncurrent Liabilities | Level 3
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		0		0		0
Fair Value Measured on a Recurring Basis | Other Noncurrent Liabilities | Other Derivative Instruments | Commodity Trading
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		8		8		47
Netting	[2]	(6)		(6)		(38)
Derivative Liability, Net		2		2		9
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		4		7
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		4		4		40
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		$ 0		$ 0		$ 0

[1] Recorded to cost of natural gas sold and transported. These losses are subject to cost-recovery mechanisms and reclassified out of income to a regulatory asset, as appropriate.

[2] PSCo nets derivative instruments and related collateral on its consolidated balance sheets when supported by a legally enforceable master netting agreement. At Sept. 30, 2023 and Dec. 31, 2022, derivative assets and liabilities include no obligations to return cash collateral. At Sept. 30, 2023 and Dec. 31, 2022, derivative assets and liabilities include rights to reclaim cash collateral of $7 million and $46 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.