CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Other comprehensive income (loss):
Net tax on reclassification of net unrealized loss on interest rate swaps during the period, tax	$ 50	$ 1,577	$ 6,234
Net unrealized gain (loss) from pension and postretirement plans, tax	(45,890)	41,773	(7,469)
Reclassification of net unrealized loss on energy derivative instruments during the period, tax	200	20	200
PUGET SOUND ENERGY, INC.
Other comprehensive income (loss):
Net unrealized gain (loss) from pension and postretirement plans, tax	(41,395)	47,705	(3,911)
Reclassification of net unrealized loss on energy derivative instruments during the period, tax	722	1,373	4,500
Amortization of treasury interest rate swaps to earnings, tax	$ 171	$ 171	$ 171