CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Parent [Line Items]
Net income (loss)	$ 905	$ 57,692	$ 168,380	$ 146,171
Other comprehensive income (loss):
Reclassification of net unrealized (gain) loss on interest rate swaps during the period, net of tax		7,088	1,715	9,596
Net unrealized gain (loss) from pension and postretirement plans, net of tax	(1,107)	(104)	(760)	(209)
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, Net of Tax	0	122	(107)	(73)
Other comprehensive income (loss)	(246)	7,106	848	9,314
Comprehensive income (loss)	659	64,798	169,228	155,485
Subsidiaries [Member]
Parent [Line Items]
Net income (loss)	26,663	80,872	206,601	193,588
Other comprehensive income (loss):
Net unrealized gain (loss) from pension and postretirement plans, net of tax	1,879	1,227	5,265	3,643
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, Net of Tax	0	2,869	1,811	4,791
Amortization Of Financing Cash Flow Hedge Contracts To Earnings During Period Net Of Tax	79	79	158	159
Other comprehensive income (loss)	1,958	4,175	7,234	8,593
Comprehensive income (loss)	28,621	85,047	213,835	202,181
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] | Interest Rate Contract [Member] | PUGET ENERGY [Member]
Other comprehensive income (loss):
Reclassification of net unrealized (gain) loss on interest rate swaps during the period, net of tax	$ 861