CONSOLIDATED BALANCE SHEETS (USD $)	Dec. 31, 2014	Dec. 31, 2013
Utility Plant [Abstract]
Electric plant	$ 7,135,206,000	$ 7,019,853,000
Gas plant	2,680,067,000	2,528,629,000
Common plant	472,926,000	504,036,000
Less: Accumulated depreciation and amortization	(1,611,220,000)	(1,373,178,000)
Net utility plant	8,676,979,000	8,679,340,000
Other property and investments:
Goodwill	1,656,513,000	1,656,513,000
Other property and investments	91,139,000	100,332,000
Total other property and investments	1,747,652,000	1,756,845,000
Current assets:
Cash and cash equivalents	37,527,000	44,302,000
Restricted cash	32,863,000	7,171,000
Accounts receivable, net of allowance for doubtful accounts	306,923,000	408,512,000
Unbilled revenue	168,039,000	219,884,000
Purchased gas adjustment receivable	21,073,000	0
Materials and supplies, at average cost	83,189,000	88,140,000
Fuel and gas inventory, at average cost	69,433,000	66,717,000
Unrealized gain on derivative instruments	21,178,000	18,867,000
Taxes	301,000	297,000
Prepaid expense and other	20,905,000	18,787,000
Power contract acquisition adjustment gain	43,843,000	48,509,000
Deferred income taxes	161,445,000	86,004,000
Total current assets	966,719,000	1,007,190,000
Other long-term and regulatory assets:
Regulatory asset for deferred income taxes	95,432,000	146,867,000
Power cost adjustment mechanism	4,623,000	0
Regulatory assets related to power contracts	29,816,000	33,753,000
Other regulatory assets	866,835,000	749,382,000
Unrealized gain on derivative instruments	3,170,000	7,733,000
Power contract acquisition adjustment gain	347,547,000	394,556,000
Other	96,275,000	130,909,000
Total other long-term and regulatory assets	1,443,698,000	1,463,200,000
Total assets	12,835,048,000	12,906,575,000
Common shareholder’s equity:
Common stock	0	0
Additional paid-in capital	3,308,957,000	3,308,957,000
Earnings reinvested in the business	271,414,000	323,007,000
Accumulated other comprehensive income (loss), net of tax	(37,043,000)	47,715,000
Total common shareholder’s equity	3,543,328,000	3,679,679,000
Long-term debt:
First mortgage bonds and senior notes	3,189,412,000	3,351,412,000
Pollution control bonds	161,860,000	161,860,000
Junior subordinated notes	250,000,000	250,000,000
Long-term debt	1,699,000,000	1,699,000,000
Debt discount and other	(218,664,000)	(229,796,000)
Total long-term debt	5,081,608,000	5,232,476,000
Total capitalization	8,624,936,000	8,912,155,000
Current liabilities:
Accounts payable	307,578,000	296,681,000
Short-term debt	85,000,000	162,000,000
Current maturities of long-term debt	162,000,000	0
Purchased gas adjustment liability	0	5,938,000
Accrued expenses:
Taxes	107,782,000	109,559,000
Salaries and wages	40,970,000	38,491,000
Interest	78,914,000	79,303,000
Unrealized loss on derivative instruments	142,195,000	48,049,000
Power Contract Acquisition Adjustment Loss Current	3,593,000	3,937,000
Other	62,464,000	60,335,000
Total current liabilities	990,496,000	804,293,000
Other Long-term and regulatory liabilities:
Deferred income taxes	1,522,357,000	1,487,005,000
Unrealized loss on derivative instruments	62,913,000	38,162,000
Power Cost Adjustment Mechanism Liability, Noncurrent	0	5,345,000
Regulatory liabilities	633,471,000	689,060,000
Regulatory Liabilities Related To Power Contracts	391,389,000	443,065,000
Power Contract Acquisition Adjustment Loss Non Current	26,223,000	29,816,000
Other deferred credits	583,263,000	497,674,000
Total other long-term and regulatory liabilities	3,219,616,000	3,190,127,000
Commitments and contingencies (Note 15)
Total capitalization and liabilities	12,835,048,000	12,906,575,000
PUGET SOUND ENERGY, INC.
Utility Plant [Abstract]
Electric plant	9,330,999,000	9,276,400,000
Gas plant	3,282,818,000	3,134,880,000
Common plant	512,842,000	565,072,000
Less: Accumulated depreciation and amortization	(4,449,680,000)	(4,297,012,000)
Net utility plant	8,676,979,000	8,679,340,000
Other property and investments:
Other property and investments	86,913,000	91,919,000
Total other property and investments	86,913,000	91,919,000
Current assets:
Cash and cash equivalents	37,466,000	44,111,000
Restricted cash	32,863,000	7,171,000
Accounts receivable, net of allowance for doubtful accounts	307,046,000	408,827,000
Unbilled revenue	168,039,000	219,884,000
Purchased gas adjustment receivable	21,073,000	0
Materials and supplies, at average cost	83,189,000	88,140,000
Fuel and gas inventory, at average cost	66,656,000	63,914,000
Unrealized gain on derivative instruments	21,178,000	18,867,000
Taxes	301,000	297,000
Prepaid expense and other	20,907,000	18,770,000
Deferred income taxes	208,447,000	141,058,000
Total current assets	967,165,000	1,011,039,000
Other long-term and regulatory assets:
Regulatory asset for deferred income taxes	94,913,000	146,350,000
Power cost adjustment mechanism	4,623,000	0
Other regulatory assets	866,793,000	749,382,000
Unrealized gain on derivative instruments	3,170,000	7,733,000
Other	89,306,000	123,125,000
Total other long-term and regulatory assets	1,058,805,000	1,026,590,000
Total assets	10,789,862,000	10,808,888,000
Common shareholder’s equity:
Common stock	859,000	859,000
Additional paid-in capital	3,246,205,000	3,246,205,000
Earnings reinvested in the business	202,622,000	289,432,000
Accumulated other comprehensive income (loss), net of tax	(170,957,000)	(95,739,000)
Total common shareholder’s equity	3,278,729,000	3,440,757,000
Long-term debt:
First mortgage bonds and senior notes	3,189,412,000	3,351,412,000
Pollution control bonds	161,860,000	161,860,000
Junior subordinated notes	250,000,000	250,000,000
Debt discount and other	(13,000)	(14,000)
Total long-term debt	3,601,259,000	3,763,258,000
Total capitalization	6,879,988,000	7,204,015,000
Current liabilities:
Accounts payable	307,572,000	296,675,000
Short-term debt	85,000,000	162,000,000
Short-term note owed to parent	28,933,000	29,598,000
Current maturities of long-term debt	162,000,000	0
Purchased gas adjustment liability	0	5,938,000
Accrued expenses:
Taxes	107,782,000	109,559,000
Salaries and wages	40,970,000	38,491,000
Interest	55,346,000	55,262,000
Unrealized loss on derivative instruments	135,973,000	41,465,000
Other	62,464,000	60,334,000
Total current liabilities	986,040,000	799,322,000
Other Long-term and regulatory liabilities:
Deferred income taxes	1,649,857,000	1,584,850,000
Unrealized loss on derivative instruments	60,063,000	31,523,000
Power Cost Adjustment Mechanism Liability, Noncurrent	0	5,345,000
Regulatory liabilities	630,651,000	686,176,000
Other deferred credits	583,263,000	497,657,000
Total other long-term and regulatory liabilities	2,923,834,000	2,805,551,000
Commitments and contingencies (Note 15)
Total capitalization and liabilities	$ 10,789,862,000	$ 10,808,888,000