CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Parent [Line Items]
Net income (loss)	$ 171,835	$ 285,728	$ 273,821
Other comprehensive income (loss):
Other Comprehensive Income Reclassification Of Net Unrealized Gain Loss On Interest Rate Swaps During Period Net Of Tax	94	2,928	11,577
Net unrealized gain (loss) from pension and postretirement plans, net of tax	(85,224)	77,579	(13,870)
Reclassification of net unrealized loss on energy derivative instruments settled during the period, net of tax	372	37	371
Other comprehensive income (loss)	(84,758)	80,544	(1,922)
Comprehensive income (loss)	87,077	366,272	271,899
PUGET SOUND ENERGY, INC.
Parent [Line Items]
Net income (loss)	236,614	356,129	356,170
Other comprehensive income (loss):
Net unrealized gain (loss) from pension and postretirement plans, net of tax	(76,876)	88,593	(7,294)
Reclassification of net unrealized loss on energy derivative instruments settled during the period, net of tax	1,341	2,549	8,358
Amortization of treasury interest rate swaps to earnings, net of tax	317	317	317
Other comprehensive income (loss)	(75,218)	91,459	1,381
Comprehensive income (loss)	$ 161,396	$ 447,588	$ 357,551