Benefit Plans and Other Postretirement Benefits (Details) (USD $)	1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 31, 2014 Plan	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Pension Benefits
Components of Net Periodic Benefit Cost [Abstract]
Service cost		$ 22,085,000	$ 24,070,000	$ 44,171,000	$ 48,141,000
Interest cost		39,155,000	35,173,000	78,310,000	70,345,000
Expected return on plan assets		(51,801,000)	(49,613,000)	(103,602,000)	(99,226,000)
Amortization of transition obligation		0	0	0	0
Amortization of prior service (credit) cost		(436,000)	1,468,000	(873,000)	2,936,000
Amortization of net loss		29,190,000	36,038,000	58,381,000	72,076,000
Net periodic benefit cost		38,193,000	47,136,000	76,387,000	94,272,000
Costs not recognized due to the effects of regulation		(6,604,000)	(7,089,000)	(13,656,000)	(14,936,000)
Net benefit cost recognized for financial reporting		31,589,000	40,047,000	62,731,000	79,336,000
Total contributions to Xcel Energy's pension plans during the period	130,000,000
Number of pension plans to which contributions were made	3
Postretirement Health Care Benefits
Components of Net Periodic Benefit Cost [Abstract]
Service cost		864,000	1,182,000	1,728,000	2,364,000
Interest cost		8,507,000	8,417,000	17,014,000	16,834,000
Expected return on plan assets		(8,488,000)	(8,253,000)	(16,977,000)	(16,506,000)
Amortization of transition obligation		0	206,000	0	412,000
Amortization of prior service (credit) cost		(2,672,000)	(2,438,000)	(5,344,000)	(4,876,000)
Amortization of net loss		2,935,000	5,646,000	5,870,000	11,292,000
Net periodic benefit cost		1,146,000	4,760,000	2,291,000	9,520,000
Costs not recognized due to the effects of regulation		0	0	0	0
Net benefit cost recognized for financial reporting		$ 1,146,000	$ 4,760,000	$ 2,291,000	$ 9,520,000