CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Other comprehensive income (loss):
Net tax on reclassification of net unrealized loss on interest rate swaps during the period, tax	$ 3,817	$ 8,486	$ 5,167	$ 10,766
Net unrealized gain (loss) from pension and postretirement plans, tax	(56)	(142)	(112)	(283)
Reclassification of net unrealized loss on energy derivative instruments during the period, tax	66	95	(39)	196
PUGET SOUND ENERGY, INC. [Member]
Other comprehensive income (loss):
Net unrealized gain (loss) from pension and postretirement plans, tax	661	931	1,962	2,196
Reclassification of net unrealized loss on energy derivative instruments during the period, tax	1,545	1,715	2,580	8,495
Amortization of treasury interest rate swaps to earnings, tax	$ 43	$ 43	$ 85	$ 85