CONSOLIDATED STATEMENTS OF CAPITALIZATION - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Schedule of Capitalization, Long-term Debt [Line Items]
Less current maturities	$ 250,000	$ 450,000
Less current maturities	255,529	657,021
Long-term debt, noncurrent	14,194,718	12,398,880
Common Stockholders' Equity
Common stock — 1,000,000,000 shares authorized of $2.50 par value; 507,222,795 and 507,535,523 shares outstanding at Dec. 31, 2016 and Dec. 31, 2015, respectively	1,268,057	1,268,839
Additional paid in capital	5,881,494	5,889,106
Retained earnings	3,981,652	3,552,728
Accumulated other comprehensive loss	(110,354)	(109,753)
Total common stockholders’ equity	11,020,849	10,600,920
NSP-Minnesota
Schedule of Capitalization, Long-term Debt [Line Items]
Unamortized discount	(16,951)	(15,911)
Unamortized debt expense	(39,907)	(37,701)
Long-term Debt	4,843,165	4,496,421
Less current maturities	10	11
Long-term debt, noncurrent	4,843,155	4,496,410
NSP-Minnesota \| First Mortgage Bonds \| Series Due March 1, 2018
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	500,000	500,000
NSP-Minnesota \| First Mortgage Bonds \| Series Due Aug. 15, 2020
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	300,000	300,000
NSP-Minnesota \| First Mortgage Bonds \| Series Due Aug. 15, 2022
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	300,000	300,000
NSP-Minnesota \| First Mortgage Bonds \| Series Due May 15, 2023
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	400,000	400,000
NSP-Minnesota \| First Mortgage Bonds \| Series Due July 1, 2025
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	250,000	250,000
NSP-Minnesota \| First Mortgage Bonds \| Series Due March 1, 2028
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	150,000	150,000
NSP-Minnesota \| First Mortgage Bonds \| Series Due July 15, 2035
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	250,000	250,000
NSP-Minnesota \| First Mortgage Bonds \| Series Due June 1, 2036
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	400,000	400,000
NSP-Minnesota \| First Mortgage Bonds \| Series Due July 1, 2037
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	350,000	350,000
NSP-Minnesota \| First Mortgage Bonds \| Series Due Nov. 1, 2039
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	300,000	300,000
NSP-Minnesota \| First Mortgage Bonds \| Series Due Aug. 15, 2040
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	250,000	250,000
NSP-Minnesota \| First Mortgage Bonds \| Series Due Aug. 15, 2042
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	500,000	500,000
NSP-Minnesota \| First Mortgage Bonds \| Series Due May 15, 2044
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	300,000	300,000
NSP-Minnesota \| First Mortgage Bonds \| Series Due Aug. 15, 2045
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	300,000	300,000
NSP-Minnesota \| First Mortgage Bonds \| Series Due May 15, 2046 [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	350,000	0
NSP-Minnesota \| Other
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	23	33
PSCo
Schedule of Capitalization, Long-term Debt [Line Items]
Unamortized discount	(12,922)	(11,340)
Unamortized debt expense	(26,799)	(26,595)
Total long-term debt	4,216,206	4,105,596
Less current maturities	5,270	8,103
Long-term debt, noncurrent	4,210,936	4,097,493
PSCo \| First Mortgage Bonds \| Series Due Sept. 1, 2017
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	0	129,500
PSCo \| First Mortgage Bonds \| Series Due Aug. 1, 2018
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	300,000	300,000
PSCo \| First Mortgage Bonds \| Series Due June 1, 2019
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	400,000	400,000
PSCo \| First Mortgage Bonds \| Series Due Nov. 15, 2020
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	400,000	400,000
PSCo \| First Mortgage Bonds \| Series Due Sept. 15, 2022
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	300,000	300,000
PSCo \| First Mortgage Bonds \| Series Due March 15, 2023
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	250,000	250,000
PSCo \| First Mortgage Bonds \| Series Due May 15, 2025
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	250,000	250,000
PSCo \| First Mortgage Bonds \| Series Due Sept. 1, 2037
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	350,000	350,000
PSCo \| First Mortgage Bonds \| Series Due Aug. 1, 2038
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	300,000	300,000
PSCo \| First Mortgage Bonds \| Series Due Aug. 15, 2041
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	250,000	250,000
PSCo \| First Mortgage Bonds \| Series Due Sept. 15, 2042
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	500,000	500,000
PSCo \| First Mortgage Bonds \| Series Due March 15, 2043
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	250,000	250,000
PSCo \| First Mortgage Bonds \| Series Due March 15, 2044
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	300,000	300,000
PSCo \| First Mortgage Bonds \| Series Due June 15, 2046 [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	250,000	0
PSCo \| Capital Lease Obligations
Schedule of Capitalization, Long-term Debt [Line Items]
Capital Lease Obligations	155,927	164,031
SPS
Schedule of Capitalization, Long-term Debt [Line Items]
Unamortized discount	365	605
Unamortized debt expense	(14,507)	(12,083)
Long-term Debt	1,635,858	1,538,522
Less current maturities	0	200,000
Long-term debt, noncurrent	1,635,858	1,338,522
SPS \| First Mortgage Bonds \| Series Due Aug. 15, 2041
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	400,000	400,000
SPS \| First Mortgage Bonds \| Series Due June 15, 2024
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	350,000	350,000
SPS \| First Mortgage Bonds \| Series Due Aug. 15, 2046 [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	300,000	0
SPS \| Senior Unsecured Notes \| Senior E Due Oct. 1, 2016
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	0	200,000
SPS \| Senior Unsecured Notes \| Senior G Due Dec. 1, 2018
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	250,000	250,000
SPS \| Senior Unsecured Notes \| Senior C and D Due Oct. 1, 2033
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	100,000	100,000
SPS \| Senior Unsecured Notes \| Senior F Due Oct. 1, 2036
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	250,000	250,000
NSP-Wisconsin
Schedule of Capitalization, Long-term Debt [Line Items]
Unamortized discount	(2,865)	(3,131)
Unamortized debt expense	(4,697)	(5,144)
Long-term Debt	663,069	662,449
Less current maturities	1,123	1,131
Long-term debt, noncurrent	661,946	661,318
NSP-Wisconsin \| First Mortgage Bonds \| Series Due June 15, 2024
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	200,000	200,000
NSP-Wisconsin \| First Mortgage Bonds \| Series Due Oct. 1, 2018
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	150,000	150,000
NSP-Wisconsin \| First Mortgage Bonds \| Series Due Sept. 1, 2038
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	200,000	200,000
NSP-Wisconsin \| First Mortgage Bonds \| Series Due Oct. 1, 2042
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	100,000	100,000
NSP-Wisconsin \| City of La Crosse Resource Recovery Bond \| Series Due Nov. 1, 2021
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	18,600	18,600
NSP-Wisconsin \| Fort McCoy System Acquisition \| Due Oct. 15, 2030
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	456	490
NSP-Wisconsin \| Other
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	1,575	1,634
Other Subsidiaries
Schedule of Capitalization, Long-term Debt [Line Items]
Unamortized debt expense	(365)	(417)
Long-term Debt	30,621	30,838
Less current maturities	763	709
Long-term debt, noncurrent	29,858	30,129
Other Subsidiaries \| Various Eloigne Co. Affordable Housing Project Notes \| Due 2017-2052
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	30,986	31,255
Xcel Energy Inc.
Schedule of Capitalization, Long-term Debt [Line Items]
Unamortized discount	(2,380)	(5,551)
Unamortized debt expense	(22,771)	(9,899)
Total long-term debt	3,061,328	2,222,075
Less current maturities	248,363	447,067
Long-term debt, noncurrent	2,874,851	1,838,529
Long-term debt, noncurrent	2,812,965	1,775,008
Common Stockholders' Equity
Total common stockholders’ equity	11,020,849	10,600,920
Xcel Energy Inc. \| Senior Unsecured Notes \| Series Due May 9, 2016
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	0	450,000
Xcel Energy Inc. \| Senior Unsecured Notes \| Series Due April 1, 2017
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	0	253,979
Xcel Energy Inc. \| Senior Unsecured Notes \| Series Due June 1, 2017
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	250,000	250,000
Xcel Energy Inc. \| Senior Unsecured Notes \| Series Due May 15, 2020
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	550,000	550,000
Xcel Energy Inc. \| Senior Unsecured Notes \| Series Due March 15, 2021 [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	400,000	0
Xcel Energy Inc. \| Senior Unsecured Notes \| Series Due March 15, 2022 [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	300,000	0
Xcel Energy Inc. \| Senior Unsecured Notes \| Series Due June 1, 2025
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	600,000	250,000
Xcel Energy Inc. \| Senior Unsecured Notes \| Series Due Dec. 1, 2026 [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	500,000	0
Xcel Energy Inc. \| Senior Unsecured Notes \| Series Due July 1, 2036
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	300,000	300,000
Xcel Energy Inc. \| Senior Unsecured Notes \| Series Due Sept. 15, 2041
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term Debt, Gross	250,000	250,000
Xcel Energy Inc. \| Capital Lease Obligations
Schedule of Capitalization, Long-term Debt [Line Items]
Capital Lease Obligations	$ (63,521)	$ (66,454)

Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

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Reference 3: 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(31))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

-- None. No documentation exists for this element. --

+ References

No definition available.

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