CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Parent [Line Items]
Net income (loss)	$ 88,480	$ 107,431
Other comprehensive income (loss):
Reclassification of net unrealized loss on interest rate swaps during the period, net of tax	2,508	4,233
Net unrealized gain (loss) from pension and postretirement plans, net of tax	(107)	(262)
Reclassification of net unrealized loss on energy derivative instruments settled during the period, net of tax	(195)	187
Other comprehensive income (loss)	2,206	4,158
Comprehensive income (loss)	90,686	111,589
PUGET SOUND ENERGY, INC. [Member]
Parent [Line Items]
Net income (loss)	112,716	103,439
Other comprehensive income (loss):
Net unrealized gain (loss) from pension and postretirement plans, net of tax	2,416	1,398
Reclassification of net unrealized loss on energy derivative instruments settled during the period, net of tax	1,923	12,590
Amortization of financing cash flow hedge contracts to earnings, net of tax	79	80
Other comprehensive income (loss)	4,418	14,068
Comprehensive income (loss)	$ 117,134	$ 117,507