Borrowings and Other Financing Instruments, Long-Term Borrowings and Other Financing Instruments (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
2017	$ 256
2018	1,206
2019	406
2020	1,257
2021	425
Xcel Energy Inc. \| Senior Unsecured Notes \| Series Due March 15, 2021 [Member]
Long-Term Borrowings and Other Financing Instruments [Abstract]
Face amount	$ 400
Interest rate, stated percentage (in hundredths)	2.40%
Maturity Date	Mar. 15, 2021
Xcel Energy Inc. \| Senior Unsecured Notes \| Series Due June 1, 2025
Long-Term Borrowings and Other Financing Instruments [Abstract]
Face amount	$ 350	$ 250
Interest rate, stated percentage (in hundredths)	3.30%	3.30%
Maturity Date	Jun. 01, 2025	Jun. 01, 2025
Xcel Energy Inc. \| Senior Unsecured Notes \| Series Due March 15, 2022 [Member]
Long-Term Borrowings and Other Financing Instruments [Abstract]
Face amount	$ 300
Interest rate, stated percentage (in hundredths)	2.60%
Maturity Date	Mar. 15, 2022
Xcel Energy Inc. \| Senior Unsecured Notes \| Series Due Dec. 1, 2026 [Member]
Long-Term Borrowings and Other Financing Instruments [Abstract]
Face amount	$ 500
Interest rate, stated percentage (in hundredths)	3.35%
Maturity Date	Dec. 01, 2026
Xcel Energy Inc. \| Senior Unsecured Notes \| Series Due June 1, 2017
Long-Term Borrowings and Other Financing Instruments [Abstract]
Face amount		$ 250
Interest rate, stated percentage (in hundredths)	1.20%	1.20%
Maturity Date	Jun. 01, 2017	Jun. 01, 2017
PSCo \| First Mortgage Bonds \| Series Due June 15, 2046 [Member]
Long-Term Borrowings and Other Financing Instruments [Abstract]
Face amount	$ 250
Interest rate, stated percentage (in hundredths)	3.55%	3.55%
Maturity Date	Jun. 15, 2046	Jun. 15, 2046
PSCo \| First Mortgage Bonds \| Series Due May 15, 2025
Long-Term Borrowings and Other Financing Instruments [Abstract]
Face amount		$ 250
Interest rate, stated percentage (in hundredths)	2.90%	2.90%
Maturity Date	May 15, 2025	May 15, 2025
NSP-Minnesota \| First Mortgage Bonds \| Series Due May 15, 2046 [Member]
Long-Term Borrowings and Other Financing Instruments [Abstract]
Face amount	$ 350
Interest rate, stated percentage (in hundredths)	3.60%
Maturity Date	May 15, 2046
NSP-Minnesota \| First Mortgage Bonds \| Series Due Aug. 15, 2020
Long-Term Borrowings and Other Financing Instruments [Abstract]
Face amount		$ 300
Interest rate, stated percentage (in hundredths)	2.20%	2.20%
Maturity Date	Aug. 15, 2020	Aug. 15, 2020
NSP-Minnesota \| First Mortgage Bonds \| Series Due Aug. 15, 2045
Long-Term Borrowings and Other Financing Instruments [Abstract]
Face amount		$ 300
Interest rate, stated percentage (in hundredths)	4.00%	4.00%
Maturity Date	Aug. 15, 2045	Aug. 15, 2045
SPS \| First Mortgage Bonds \| Series Due Aug. 15, 2046 [Member]
Long-Term Borrowings and Other Financing Instruments [Abstract]
Face amount	$ 300
Interest rate, stated percentage (in hundredths)	3.40%
Maturity Date	Aug. 15, 2046
SPS \| First Mortgage Bonds \| Series Due June 15, 2024
Long-Term Borrowings and Other Financing Instruments [Abstract]
Face amount		$ 200
Interest rate, stated percentage (in hundredths)	3.30%	3.30%
Maturity Date	Jun. 15, 2024	Jun. 15, 2024
NSP-Wisconsin \| First Mortgage Bonds \| Series Due June 15, 2024
Long-Term Borrowings and Other Financing Instruments [Abstract]
Face amount		$ 100
Interest rate, stated percentage (in hundredths)	3.30%	3.30%
Maturity Date	Jun. 15, 2024	Jun. 15, 2024

Face (par) amount of debt instrument at time of issuance.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

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Balance Type:	credit
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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(2))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- References

No definition available.

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- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04.(a))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6802200&loc=d3e1835-112601

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- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6802200&loc=d3e1835-112601

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04.(a))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690

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- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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