Benefit Plans and Other Postretirement Benefits (Details) (USD $)	1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 31, 2014	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Pension Benefits
Components of Net Periodic Benefit Cost (Credit) [Abstract]
Service cost		$ 2,296,000	$ 2,403,000	$ 4,592,000	$ 4,807,000
Interest cost		5,111,000	4,477,000	10,222,000	8,954,000
Expected return on plan assets		(6,545,000)	(5,992,000)	(13,090,000)	(11,985,000)
Amortization of prior service cost (credit)		13,000	217,000	27,000	435,000
Amortization of net loss (gain)		3,331,000	4,287,000	6,663,000	8,574,000
Net periodic benefit cost (credit)		4,206,000	5,392,000	8,414,000	10,785,000
Credits (costs) not recognized due to the effects of regulation		708,000	(317,000)	1,415,000	(1,392,000)
Net benefit cost (credit) recognized for financial reporting		4,914,000	5,075,000	9,829,000	9,393,000
Total contributions to the pension plans during the period	4,400,000
Postretirement Health Care Benefits
Components of Net Periodic Benefit Cost (Credit) [Abstract]
Service cost		311,000	342,000	623,000	684,000
Interest cost		643,000	588,000	1,286,000	1,176,000
Expected return on plan assets		(811,000)	(796,000)	(1,623,000)	(1,592,000)
Amortization of prior service cost (credit)		(101,000)	(121,000)	(201,000)	(242,000)
Amortization of net loss (gain)		(81,000)	(1,000)	(161,000)	(3,000)
Net periodic benefit cost (credit)		(39,000)	12,000	(76,000)	23,000
Credits (costs) not recognized due to the effects of regulation		0	0	0	0
Net benefit cost (credit) recognized for financial reporting		(39,000)	12,000	(76,000)	23,000
Xcel Energy Inc. | Pension Benefits
Components of Net Periodic Benefit Cost (Credit) [Abstract]
Total contributions to the pension plans during the period	$ 130,000,000
Number of Xcel Energy's pension plans to which contributions were made	3