Fair Value Measurements Assets and Liabilities (Details) (USD $)	3 Months Ended					3 Months Ended					3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013		Jun. 30, 2013	Mar. 31, 2014 Electric portfolio [Member]		Mar. 31, 2013 Electric portfolio [Member]		Jun. 30, 2013 Electric portfolio [Member]	Mar. 31, 2014 Natural gas portfolio [Member]		Mar. 31, 2013 Natural gas portfolio [Member]		Jun. 30, 2013 Natural gas portfolio [Member]	Mar. 31, 2014 Commodity Contract [Member]	Dec. 31, 2013 Commodity Contract [Member]	Mar. 31, 2014 Fair Value, Measurements, Recurring [Member] PUGET ENERGY [Member] Level 2 [Member]	Dec. 31, 2013 Fair Value, Measurements, Recurring [Member] PUGET ENERGY [Member] Level 2 [Member]	Mar. 31, 2014 Fair Value, Measurements, Recurring [Member] PUGET ENERGY [Member] Level 2 [Member] Interest Rate Contract [Member]	Dec. 31, 2013 Fair Value, Measurements, Recurring [Member] PUGET ENERGY [Member] Level 2 [Member] Interest Rate Contract [Member]	Mar. 31, 2014 Fair Value, Measurements, Recurring [Member] PUGET ENERGY [Member] Level 3 [Member]	Dec. 31, 2013 Fair Value, Measurements, Recurring [Member] PUGET ENERGY [Member] Level 3 [Member]	Mar. 31, 2014 Fair Value, Measurements, Recurring [Member] PUGET ENERGY [Member] Level 3 [Member] Interest Rate Contract [Member]	Dec. 31, 2013 Fair Value, Measurements, Recurring [Member] PUGET ENERGY [Member] Level 3 [Member] Interest Rate Contract [Member]	Mar. 31, 2014 Fair Value, Measurements, Recurring [Member] PUGET ENERGY [Member] Total [Member]	Dec. 31, 2013 Fair Value, Measurements, Recurring [Member] PUGET ENERGY [Member] Total [Member]	Mar. 31, 2014 Fair Value, Measurements, Recurring [Member] PUGET ENERGY [Member] Total [Member] Interest Rate Contract [Member]	Dec. 31, 2013 Fair Value, Measurements, Recurring [Member] PUGET ENERGY [Member] Total [Member] Interest Rate Contract [Member]	Mar. 31, 2014 Fair Value, Measurements, Recurring [Member] Subsidiaries [Member] Level 2 [Member]	Dec. 31, 2013 Fair Value, Measurements, Recurring [Member] Subsidiaries [Member] Level 2 [Member]	Mar. 31, 2014 Fair Value, Measurements, Recurring [Member] Subsidiaries [Member] Level 2 [Member] Commodity Contract [Member] Electric portfolio [Member]	Dec. 31, 2013 Fair Value, Measurements, Recurring [Member] Subsidiaries [Member] Level 2 [Member] Commodity Contract [Member] Electric portfolio [Member]	Mar. 31, 2014 Fair Value, Measurements, Recurring [Member] Subsidiaries [Member] Level 2 [Member] Commodity Contract [Member] Natural gas portfolio [Member]	Dec. 31, 2013 Fair Value, Measurements, Recurring [Member] Subsidiaries [Member] Level 2 [Member] Commodity Contract [Member] Natural gas portfolio [Member]	Mar. 31, 2014 Fair Value, Measurements, Recurring [Member] Subsidiaries [Member] Level 3 [Member]	Dec. 31, 2013 Fair Value, Measurements, Recurring [Member] Subsidiaries [Member] Level 3 [Member]	Mar. 31, 2014 Fair Value, Measurements, Recurring [Member] Subsidiaries [Member] Level 3 [Member] Commodity Contract [Member] Electric portfolio [Member]		Dec. 31, 2013 Fair Value, Measurements, Recurring [Member] Subsidiaries [Member] Level 3 [Member] Commodity Contract [Member] Electric portfolio [Member]	Mar. 31, 2014 Fair Value, Measurements, Recurring [Member] Subsidiaries [Member] Level 3 [Member] Commodity Contract [Member] Natural gas portfolio [Member]		Dec. 31, 2013 Fair Value, Measurements, Recurring [Member] Subsidiaries [Member] Level 3 [Member] Commodity Contract [Member] Natural gas portfolio [Member]	Mar. 31, 2014 Fair Value, Measurements, Recurring [Member] Subsidiaries [Member] Total [Member]	Dec. 31, 2013 Fair Value, Measurements, Recurring [Member] Subsidiaries [Member] Total [Member]	Mar. 31, 2014 Fair Value, Measurements, Recurring [Member] Subsidiaries [Member] Total [Member] Commodity Contract [Member] Electric portfolio [Member]	Dec. 31, 2013 Fair Value, Measurements, Recurring [Member] Subsidiaries [Member] Total [Member] Commodity Contract [Member] Electric portfolio [Member]	Mar. 31, 2014 Fair Value, Measurements, Recurring [Member] Subsidiaries [Member] Total [Member] Commodity Contract [Member] Natural gas portfolio [Member]	Dec. 31, 2013 Fair Value, Measurements, Recurring [Member] Subsidiaries [Member] Total [Member] Commodity Contract [Member] Natural gas portfolio [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized Gain (Loss) on Derivatives and Commodity Contracts						$ (9,200,000)		$ 1,400,000
Derivative Assets																51,709,000	26,600,000													44,119,000	20,109,000	18,866,000	14,661,000	25,253,000	5,448,000	7,590,000	6,491,000	5,040,000	[1]	3,818,000	2,550,000	[1]	2,673,000	51,709,000	26,600,000	23,906,000	18,479,000	27,803,000	8,121,000
Derivative Liabilities																		12,126,000	13,223,000	12,126,000	13,223,000	0	0	0	0	12,126,000	13,223,000	12,126,000	13,223,000	25,232,000	50,715,000	14,719,000	18,073,000	10,513,000	32,642,000	23,299,000	22,273,000	19,646,000	[1]	19,239,000	3,653,000	[1]	3,034,000	48,531,000	72,988,000	34,365,000	37,312,000	14,166,000	35,676,000
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	(15,782,000)		(35,526,000)		(27,976,000)	(15,421,000)		(33,924,000)		(26,442,000)	(361,000)		(1,602,000)		(1,534,000)
Included in earnings	(2,745,000)	[2]	1,598,000	[2]		(2,745,000)	[2]	1,598,000	[2]		0	[2]	0	[2]
Included in regulatory assets/liabilities	259,000		674,000			0		0			259,000		674,000
Settlements	(89,000)	[3]	5,651,000	[3]		321,000	[3]	6,384,000	[3]		(410,000)	[3]	(733,000)	[3]
Transferred into Level 3	2,515,000		(7,700,000)			3,100,000		(7,700,000)			(585,000)		0
Transferred out of Level 3	133,000		7,327,000			139,000		7,200,000			(6,000)		127,000
Balance at end of period	$ (15,709,000)				$ (27,976,000)	$ (14,606,000)				$ (26,442,000)	$ (1,103,000)				$ (1,534,000)

[1] 1 The valuation techniques, unobservable inputs and ranges are the same for asset and liability positions

[2] 1 Income Statement location: Unrealized (gain) loss on derivative instruments, net. Includes unrealized gains (losses) on derivatives still held in position as of the reporting date for electric derivatives of $(9.2) million and $1.4 million for the three months ended March 31, 2014 and 2013, respectively.

[3] 2 The Company had no purchases, sales or issuances during the reported periods.