Leases (Schedule of Operating Lease Expense) (Details) (PUGET SOUND ENERGY, INC., USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
PUGET SOUND ENERGY, INC.
Operating Leases, Rent Expense, Net [Abstract]
Operating lease expense net of sublease receipts	$ 29,661	$ 24,789	$ 22,493