Fair Value Measurements Assets and Liabilities (Details) (USD $)	3 Months Ended				6 Months Ended				3 Months Ended				6 Months Ended				3 Months Ended				6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014 Electric portfolio [Member]		Jun. 30, 2013 Electric portfolio [Member]		Jun. 30, 2014 Electric portfolio [Member]		Jun. 30, 2013 Electric portfolio [Member]		Jun. 30, 2014 Natural gas portfolio [Member]		Jun. 30, 2013 Natural gas portfolio [Member]		Jun. 30, 2014 Natural gas portfolio [Member]		Jun. 30, 2013 Natural gas portfolio [Member]		Jun. 30, 2014 Commodity Contract [Member]	Dec. 31, 2013 Commodity Contract [Member]	Jun. 30, 2014 Interest Rate Contract [Member]		Dec. 31, 2013 Interest Rate Contract [Member]		Jun. 30, 2014 Fair Value, Measurements, Recurring [Member] Parent Company [Member] Level 2 [Member]	Dec. 31, 2013 Fair Value, Measurements, Recurring [Member] Parent Company [Member] Level 2 [Member]	Jun. 30, 2014 Fair Value, Measurements, Recurring [Member] Parent Company [Member] Level 2 [Member] Interest Rate Contract [Member]	Dec. 31, 2013 Fair Value, Measurements, Recurring [Member] Parent Company [Member] Level 2 [Member] Interest Rate Contract [Member]	Jun. 30, 2014 Fair Value, Measurements, Recurring [Member] Parent Company [Member] Level 3 [Member]	Dec. 31, 2013 Fair Value, Measurements, Recurring [Member] Parent Company [Member] Level 3 [Member]	Jun. 30, 2014 Fair Value, Measurements, Recurring [Member] Parent Company [Member] Level 3 [Member] Interest Rate Contract [Member]	Dec. 31, 2013 Fair Value, Measurements, Recurring [Member] Parent Company [Member] Level 3 [Member] Interest Rate Contract [Member]	Jun. 30, 2014 Fair Value, Measurements, Recurring [Member] Parent Company [Member] Total [Member]	Dec. 31, 2013 Fair Value, Measurements, Recurring [Member] Parent Company [Member] Total [Member]	Jun. 30, 2014 Fair Value, Measurements, Recurring [Member] Parent Company [Member] Total [Member] Interest Rate Contract [Member]	Dec. 31, 2013 Fair Value, Measurements, Recurring [Member] Parent Company [Member] Total [Member] Interest Rate Contract [Member]	Jun. 30, 2014 Fair Value, Measurements, Recurring [Member] Subsidiaries [Member] Level 2 [Member]	Dec. 31, 2013 Fair Value, Measurements, Recurring [Member] Subsidiaries [Member] Level 2 [Member]	Jun. 30, 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]	Jun. 30, 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]	Jun. 30, 2014 Fair Value, Measurements, Recurring [Member] Subsidiaries [Member] Level 3 [Member]	Dec. 31, 2013 Fair Value, Measurements, Recurring [Member] Subsidiaries [Member] Level 3 [Member]	Jun. 30, 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]		Jun. 30, 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]		Jun. 30, 2014 Fair Value, Measurements, Recurring [Member] Subsidiaries [Member] Total [Member]	Dec. 31, 2013 Fair Value, Measurements, Recurring [Member] Subsidiaries [Member] Total [Member]	Jun. 30, 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]	Jun. 30, 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									$ 4,700,000		$ (15,600,000)		$ 100,000		$ (14,200,000)
Derivative Assets																									52,083,000	26,600,000																	38,238,000	20,109,000	15,882,000	14,661,000	22,356,000	5,448,000	13,845,000	6,491,000	11,020,000	[1]	3,818,000	[1]	2,825,000	[1]	2,673,000	[1]	52,083,000	26,600,000	26,902,000	18,479,000	25,181,000	8,121,000
Derivative Liability																									33,102,000	72,988,000	12,349,000	[2]	13,223,000	[2]	12,349,000	13,223,000	12,349,000	13,223,000	0	0	0	0	12,349,000	13,223,000	12,349,000	13,223,000	14,291,000	50,715,000	4,554,000	18,073,000	9,737,000	32,642,000	18,811,000	22,273,000	15,713,000	[1]	19,239,000	[1]	3,098,000	[1]	3,034,000	[1]	33,102,000	72,988,000	20,267,000	37,312,000	12,835,000	35,676,000
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	(15,709,000)		(27,976,000)		(15,782,000)		(35,526,000)		(14,606,000)		(26,442,000)		(15,421,000)		(33,924,000)		(1,103,000)		(1,534,000)		(361,000)		(1,602,000)
Included in earnings	7,800,000	[3]	(12,799,000)	[3]	5,055,000	[3]	(11,201,000)	[3]	7,800,000	[3]	(12,799,000)	[3]	5,055,000	[3]	(11,201,000)	[3]	0	[3]	0	[3]	0	[3]	0	[3]
Included in regulatory assets/liabilities	2,120,000		(684,000)		2,379,000		(10,000)		0		0		0		0		2,120,000		(684,000)		2,379,000		(10,000)
Settlements	1,591,000	[4]	2,183,000	[4]	1,502,000	[4]	7,834,000	[4]	1,757,000	[4]	2,678,000	[4]	2,078,000	[4]	9,062,000	[4]	(166,000)	[4]	(495,000)	[4]	(576,000)	[4]	(1,228,000)	[4]
Transferred into Level 3	0		(830,000)		2,515,000		(8,530,000)		0		(830,000)		3,100,000		(8,530,000)		0		0		(585,000)		0
Transferred out of Level 3	(768,000)		334,000		(635,000)		7,661,000		356,000		494,000		495,000		7,694,000		(1,124,000)		(160,000)		(1,130,000)		(33,000)
Balance at end of period	$ (4,966,000)		$ (39,772,000)		$ (4,966,000)		$ (39,772,000)		$ (4,693,000)		$ (36,899,000)		$ (4,693,000)		$ (36,899,000)		$ (273,000)		$ (2,873,000)		$ (273,000)		$ (2,873,000)

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

[2] 2 Interest Rate Swap Contracts are only held at Puget Energy.

[3] 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 $4.7 million and $(15.6) million for the three months ended June 30, 2014 and 2013, respectively. 2 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 $0.1 million and $(14.2) million for the six months ended June 30, 2014 and 2013, respectively.

[4] 3 The Company had no purchases, sales or issuances during the reported periods