Puget Sound Energy 10-K 2 Mar 15 2014 FY Annual report Financial data

Document_And_Entity_Informatio

Document And Entity Information (USD $)	12 Months Ended
	Dec. 31, 2014	Jun. 30, 2014
Entity Information [Line Items]
Entity Registrant Name	PUGET ENERGY INC /WA
Entity Central Index Key	1085392
Current Fiscal Year End Date	-19
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Public Float		$0
Entity Common Stock, Shares Outstanding	200
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Document Type	10-K
Amendment Flag	FALSE
Document Period End Date	31-Dec-14
PUGET SOUND ENERGY, INC.
Entity Information [Line Items]
Entity Registrant Name	PUGET SOUND ENERGY INC
Entity Central Index Key	81100
Current Fiscal Year End Date	-19
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Public Float		$0
Entity Common Stock, Shares Outstanding	85,903,791
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Document Type	10-K
Amendment Flag	FALSE
Document Period End Date	31-Dec-14

CONSOLIDATED_STATEMENTS_OF_INC

CONSOLIDATED STATEMENTS OF INCOME (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating revenue:
Electric	$2,083,797	$2,156,920	$2,128,230
Gas	1,012,859	1,028,357	1,086,095
Other	16,515	2,020	831
Total operating revenue	3,113,171	3,187,297	3,215,156
Energy costs:
Purchased electricity	514,087	541,905	622,288
Electric generation fuel	263,493	261,332	204,956
Residential exchange	-129,036	-81,053	-73,555
Purchased gas	458,691	488,201	538,612
Unrealized (gain) loss on derivative instruments, net	84,146	-102,744	-133,606
Utility operations and maintenance	550,146	529,939	512,765
Non-utility expense and other	13,109	-3,555	814
Depreciation	370,962	364,324	337,952
Amortization	-5,356	24,631	55,819
Conservation Amortization	104,096	105,897	114,177
Taxes other than income taxes	310,982	303,260	319,399
Total operating expenses	2,535,320	2,432,137	2,499,621
Operating income (loss)	577,851	755,160	715,535
Other income (deductions):
Other income	24,038	38,693	49,069
Other expense	-7,457	-7,134	-11,770
Non-hedged interest rate swap expense	-3,915	2,420	-4,288
Interest charges:
AFUDC	5,611	11,261	22,216
Interest expense	-367,308	-392,264	-392,216
Income (loss) before income taxes	228,820	408,136	378,546
Income tax (benefit) expense	56,985	122,408	104,725
Net income (loss)	171,835	285,728	273,821
PUGET SOUND ENERGY, INC.
Operating revenue:
Electric	2,083,797	2,156,920	2,128,230
Gas	1,012,859	1,028,357	1,086,095
Other	19,467	2,058	1,934
Total operating revenue	3,116,123	3,187,335	3,216,259
Energy costs:
Purchased electricity	514,087	541,905	622,288
Electric generation fuel	263,493	261,332	204,956
Residential exchange	-129,036	-81,053	-73,555
Purchased gas	458,691	488,201	538,612
Unrealized (gain) loss on derivative instruments, net	85,636	-98,880	-119,120
Utility operations and maintenance	550,146	529,939	512,765
Non-utility expense and other	23,729	12,205	9,977
Depreciation	370,962	364,324	337,952
Amortization	-5,356	24,631	55,819
Conservation Amortization	104,096	105,897	114,177
Taxes other than income taxes	310,982	303,260	319,399
Total operating expenses	2,547,430	2,451,761	2,523,270
Operating income (loss)	568,693	735,574	692,989
Other income (deductions):
Other income	24,036	38,690	49,056
Other expense	-7,457	-7,134	-11,770
Interest charges:
AFUDC	5,611	11,261	22,216
Interest expense	-264,745	-261,264	-246,811
Interest expense on parent note	-182	-112	-202
Income (loss) before income taxes	325,956	517,015	505,478
Income tax (benefit) expense	89,342	160,886	149,308
Net income (loss)	$236,614	$356,129	$356,170

CONSOLIDATED_STATEMENTS_OF_COM

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $)	12 Months Ended
In Thousands, unless otherwise specified	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

CONSOLIDATED_STATEMENTS_OF_COM1

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Other comprehensive income (loss):
Net tax on reclassification of net unrealized loss on interest rate swaps during the period, tax	$50	$1,577	$6,234
Net unrealized gain (loss) from pension and postretirement plans, tax	-45,890	41,773	-7,469
Reclassification of net unrealized loss on energy derivative instruments during the period, tax	200	20	200
PUGET SOUND ENERGY, INC.
Other comprehensive income (loss):
Net unrealized gain (loss) from pension and postretirement plans, tax	-41,395	47,705	-3,911
Reclassification of net unrealized loss on energy derivative instruments during the period, tax	722	1,373	4,500
Amortization of treasury interest rate swaps to earnings, tax	$171	$171	$171

CONSOLIDATED_BALANCE_SHEETS

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

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Assets:
Construction work in progress	$239,690	$310,318
Current assets:
Allowance for doubtful accounts	7,385	9,932
Common shareholder’s equity:
Common stock, par value (in dollars per share)	$0.01	$0.01
Common stock, shares authorized (in shares)	1,000	1,000
Common stock, shares outstanding (in shares)	200	200
PUGET SOUND ENERGY, INC.
Assets:
Construction work in progress	239,690	310,318
Current assets:
Allowance for doubtful accounts	$7,472	$7,385
Common shareholder’s equity:
Common stock, par value (in dollars per share)	$0.01	$0.01
Common stock, shares authorized (in shares)	150,000,000	150,000,000,000
Common stock, shares outstanding (in shares)	85,903,791	85,903,791,000

CONSOLIDATED_STATEMENTS_OF_COM2

CONSOLIDATED STATEMENTS OF COMMON SHAREHOLDER'S EQUITY (USD $)	Total	Common Stock	Additional Paid-in Capital	Earnings Reinvested in the Business	Accumulated Other Comprehensive Income (Loss)	PUGET SOUND ENERGY, INC.	PUGET SOUND ENERGY, INC.	PUGET SOUND ENERGY, INC.	PUGET SOUND ENERGY, INC.	PUGET SOUND ENERGY, INC.
In Thousands, except Share data, unless otherwise specified	USD ($)		USD ($)	USD ($)	USD ($)	USD ($)	Common Stock	Additional Paid-in Capital	Earnings Reinvested in the Business	Accumulated Other Comprehensive Income (Loss)
							USD ($)	USD ($)	USD ($)	USD ($)
Balance at Dec. 31, 2011	$3,300,923		$3,308,957	$22,873	($30,907)	$3,222,220	$859	$3,246,205	$163,735	($188,579)
Balance (in shares) at Dec. 31, 2011		200					85,903,791
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	273,821			273,821		356,170			356,170
Common stock dividend	-88,594			-88,594		-175,625			-175,625
Other comprehensive income (loss)	-1,922				-1,922	1,381				1,381
Balance at Dec. 31, 2012	3,484,228		3,308,957	208,100	-32,829	3,404,146	859	3,246,205	344,280	-187,198
Balance (in shares) at Dec. 31, 2012		200					85,903,791
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	167,475					179,938
Balance at Mar. 31, 2013
Balance at Dec. 31, 2012	3,484,228		3,308,957	208,100	-32,829	3,404,146	859	3,246,205	344,280	-187,198
Balance (in shares) at Dec. 31, 2012		200					85,903,791
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	285,728			285,728		356,129			356,129
Common stock dividend	-170,821			-170,821		-410,977			-410,977
Other comprehensive income (loss)	80,544				80,544	91,459				91,459
Balance at Dec. 31, 2013	3,679,679		3,308,957	323,007	47,715	3,440,757	859	3,246,205	289,432	-95,739
Balance (in shares) at Dec. 31, 2013	200	200				85,903,791,000	85,903,791
Balance at Sep. 30, 2013
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	108,808					122,923
Balance at Dec. 31, 2013	3,679,679		3,308,957			3,440,757	859	3,246,205
Balance (in shares) at Dec. 31, 2013	200	200				85,903,791,000	85,903,791
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	107,592					121,083
Balance at Mar. 31, 2014
Balance at Dec. 31, 2013	3,679,679		3,308,957	323,007	47,715	3,440,757	859	3,246,205	289,432	-95,739
Balance (in shares) at Dec. 31, 2013	200	200				85,903,791,000	85,903,791
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	171,835			171,835		236,614			236,614
Common stock dividend	-223,428			-223,428		-323,424			-323,424
Other comprehensive income (loss)	-84,758				-84,758	-75,218				-75,218
Balance at Dec. 31, 2014	3,543,328		3,308,957	271,414	-37,043	3,278,729	859	3,246,205	202,622	-170,957
Balance (in shares) at Dec. 31, 2014	200	200				85,903,791	85,903,791
Balance at Sep. 30, 2014
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	36,088					54,640
Balance at Dec. 31, 2014	$3,543,328		$3,308,957			$3,278,729	$859	$3,246,205
Balance (in shares) at Dec. 31, 2014	200	200				85,903,791	85,903,791

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating activities:
Net income (loss)	$171,835	$285,728	$273,821
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation	370,962	364,324	337,952
Amortization	-5,356	24,631	55,819
Conservation amortization	104,096	105,897	114,177
Deferred income taxes and tax credits, net	56,984	122,409	100,457
Gain (Loss) on Sale of Properties	-4,071	0	0
Net unrealized (gain) loss on derivative instruments	80,139	-106,540	-146,680
Derivative contracts classified as financing activities due to merger	16,349	34,250	92,681
AFUDC - equity	-7,002	-15,930	-25,469
Funding of pension liability	-18,000	-20,400	-22,800
Regulatory assets	-219,604	-122,549	-170,374
Regulatory liabilities	-8,730	50,025	14,054
Other long-term assets	-6,003	-24,877	-1,644
Other long-term liabilities	29,765	180,015	95,166
Change in certain current assets and liabilities:
Accounts receivable and unbilled revenue	153,434	-103,949	35,537
Materials and supplies	4,951	-5,787	-6,284
Fuel and gas inventory	-2,742	21,633	11,527
Taxes	-4	4,499	6,174
Prepayments and other	-2,136	-5,357	393
Purchased gas adjustment	-27,011	-26,649	6,647
Accounts payable	9,098	4,597	-25,963
Taxes payable	-1,777	13,936	4,896
Accrued expenses and other	6,605	-13,838	32,598
Net cash provided by operating activities	701,782	766,068	782,685
Investing activities:
Construction expenditures - excluding equity AFUDC	-493,130	-567,938	-859,791
Treasury grant payment received	107,876	0	205,261
Proceeds from disposition of assets	20,296	108,362	0
Restricted cash	-25,692	-3,471	483
Other	-4,512	-17,871	-38,923
Net cash used in investing activities	-395,162	-480,918	-692,970
Financing activities:
Change in short-term debt, net	-77,000	-26,578	148,437
Dividends paid	-223,428	-170,821	-88,594
Long-term notes and bonds issued	299,000	161,860	1,314,000
Redemption of bonds and notes	-299,000	-309,860	-1,273,000
Derivative contracts classified as financing activities due to merger	-16,349	-34,250	-92,681
Issuance cost of bonds and other	3,382	3,259	430
Net cash provided by (used in) financing activities	-313,395	-376,390	8,592
Net increase (decrease) in cash and cash equivalents	-6,775	-91,240	98,307
Cash and cash equivalents at beginning of period	44,302	135,542	37,235
Cash and cash equivalents at end of period	37,527	44,302	135,542
Supplemental cash flow information:
Cash payments for interest (net of capitalized interest)	349,402	334,041	318,305
Income Taxes Paid, Net	0	-4,500	-1,898
Capital Expenditures Incurred but Not yet Paid	51,776	49,977	79,852
PUGET SOUND ENERGY, INC.
Operating activities:
Net income (loss)	236,614	356,129	356,170
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation	370,962	364,324	337,952
Amortization	-5,356	24,631	55,819
Conservation amortization	104,096	105,897	114,177
Deferred income taxes and tax credits, net	89,342	160,886	145,040
Gain (Loss) on Sale of Properties	-4,071	0	0
Net unrealized (gain) loss on derivative instruments	85,636	-98,880	-119,120
AFUDC - equity	-7,002	-15,930	-25,469
Funding of pension liability	-18,000	-20,400	-22,800
Regulatory assets	-219,604	-122,549	-170,374
Regulatory liabilities	-8,730	50,025	14,054
Other long-term assets	-12,383	-21,932	932
Other long-term liabilities	32,972	160,596	79,789
Change in certain current assets and liabilities:
Accounts receivable and unbilled revenue	153,626	-104,059	35,285
Materials and supplies	4,951	-5,787	-6,284
Fuel and gas inventory	-2,742	21,633	11,527
Taxes	-4	4,499	6,174
Prepayments and other	-2,136	-5,357	393
Purchased gas adjustment	-27,011	-26,649	6,647
Accounts payable	9,098	4,597	-25,972
Taxes payable	-1,777	13,936	4,896
Accrued expenses and other	4,246	-9,931	-954
Net cash provided by operating activities	782,727	835,679	797,882
Investing activities:
Construction expenditures - excluding equity AFUDC	-493,130	-567,938	-859,791
Treasury grant payment received	107,876	0	205,261
Proceeds from disposition of assets	20,296	108,362	0
Restricted cash	-25,692	-3,471	483
Other	-1,683	-16,751	-18,022
Net cash used in investing activities	-392,333	-479,798	-672,069
Financing activities:
Change in short-term debt, net	-77,000	-26,578	148,437
Dividends paid	-323,424	-410,977	-175,625
Loan from (payment to) parent	-665	0	-400
Long-term notes and bonds issued	0	161,860	0
Redemption of bonds and notes	0	-174,860	0
Issuance cost of bonds and other	4,050	3,255	6,295
Net cash provided by (used in) financing activities	-397,039	-447,300	-21,293
Net increase (decrease) in cash and cash equivalents	-6,645	-91,419	104,520
Cash and cash equivalents at beginning of period	44,111	135,530	31,010
Cash and cash equivalents at end of period	37,466	44,111	135,530
Supplemental cash flow information:
Cash payments for interest (net of capitalized interest)	253,803	244,887	216,128
Income Taxes Paid, Net	0	-4,500	-1,898
Capital Expenditures Incurred but Not yet Paid	$51,776	$49,977	$79,852

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies
	Basis of Presentation
	Puget Energy, Inc. (Puget Energy) is an energy services holding company that owns Puget Sound Energy, Inc. (PSE).  PSE is a public utility incorporated in the state of Washington that furnishes electric and natural gas services in a territory covering 6,000 square miles, primarily in the Puget Sound region.  In 2009, Puget Holdings LLC (Puget Holdings), owned by a consortium of long-term infrastructure investors, completed its merger with Puget Energy (the merger).  As a result of the merger, all of Puget Energy’s common stock is indirectly owned by Puget Holdings.  The acquisition of Puget Energy was accounted for in accordance with Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) 805, “Business Combinations” (ASC 805), as of the date of the merger.  ASC 805 requires the acquirer to recognize and measure identifiable assets acquired and liabilities assumed at fair value as of the merger date.
	The consolidated financial statements of Puget Energy reflect the accounts of Puget Energy and its subsidiary, PSE.  PSE’s consolidated financial statements include the accounts of PSE and its subsidiary.  Puget Energy and PSE are collectively referred to herein as “the Company.”  The consolidated financial statements are presented after elimination of all significant intercompany items and transactions.  PSE’s consolidated financial statements continue to be accounted for on a historical basis and PSE’s financial statements do not include any ASC 805 purchase accounting adjustments.  The preparation of financial statements in conformity with U.S. Generally Accepted Accounting Principles (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period.  Actual results could differ from those estimates.
	PSE collected Washington State excise taxes (which are a component of general retail customer rates) and municipal taxes totaling $231.7 million, $243.9 million and $244.2 million for 2014, 2013 and 2012, respectively. The Company reports the collection of such taxes on a gross basis in operation revenue and as expense in taxes other than income taxes in the accompanying consolidated statements of income.
	Beginning July 1, 2013, PSE's electric and gas operations contain a revenue decoupling mechanism under which PSE's actual energy delivery revenues related to electric transmission and distribution, gas operations and general administrative costs are compared with authorized revenues allowed under the mechanism. Any differences are deferred to a regulatory asset for under recovery or regulatory liability for over recovery. Revenues associated with power costs under the Power Cost Adjustment (PCA) mechanism and Purchased Gas Adjustment (PGA) rates are excluded from the decoupling mechanism.
	Utility Plant
	Puget Energy and PSE capitalize, at original cost, additions to utility plant, including renewals and betterments.  Costs include indirect costs such as engineering, supervision, certain taxes, pension and other employee benefits and an Allowance for Funds Used During Construction (AFUDC).  Replacements of minor items of property are included in maintenance expense. When the utility plant is retired and removed from service, the original cost of the property is charged to accumulated depreciation and costs associated with removal of the property, less salvage, are charged to the cost of removal regulatory liability.
	Planned Major Maintenance
	Planned major maintenance is an activity that typically occurs when PSE overhauls or substantially upgrades various systems and equipment on its natural gas fired combustion turbines on a scheduled basis. Costs related to planned major maintenance are deferred and amortized to the next scheduled major maintenance. This accounting method also follows the Washington Utilities and Transportation Commission (Washington Commission) regulatory treatment related to these generating facilities.
	Non-Utility Property, Plant and Equipment
	For PSE, the costs of other property, plant and equipment are stated at historical cost.  Expenditures for refurbishment and improvements that significantly add to productive capacity or extend useful life of an asset are capitalized.  Replacement of minor items are expensed on a current basis.  Gains and losses on assets sold or retired are reflected in earnings.
	Depreciation and Amortization
	For financial statement purposes, the Company provides for depreciation and amortization on a straight-line basis.  Amortization is recorded for intangibles such as regulatory assets and liabilities, computer software and franchises.  The depreciation of vehicles and equipment is allocated to the asset and expense accounts based on usage.  The annual depreciation provision stated as a percent of a depreciable electric utility plant was 2.8%, 2.8% and 2.9% in 2014, 2013 and 2012, respectively; depreciable gas utility plant was 3.4%, 3.4% and 3.4% in 2014, 2013 and 2012, respectively; and depreciable common utility plant was 8.5%, 11.4% and 11.6% in 2014, 2013 and 2012, respectively.  The decrease in depreciable common utility plant that occurred between 2014 and 2013 was primarily due to asset retirement. Depreciation on other property, plant and equipment is calculated primarily on a straight-line basis over the useful lives of the assets.  The cost of removal is collected from PSE’s customers through depreciation expense and any excess is recorded as a regulatory liability.
	Goodwill
	In 2009, Puget Holdings completed its merger with Puget Energy.  Puget Energy remeasured the carrying amount of all its assets and liabilities to fair value, which resulted in recognition of approximately $1.7 billion in goodwill.  ASC 350, “Intangibles - Goodwill and Other” (ASC 350), requires that goodwill be tested for impairment at the reporting unit level on an annual basis and between annual tests if an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying value.  These events or circumstances could include a significant change in the Company’s business or regulatory outlook, legal factors, a sale or disposition of a significant portion of a reporting unit or significant changes in the financial markets which could influence the Company’s access to capital and interest rates.  Application of the goodwill impairment test requires judgment, including the identification of reporting units, assignment of assets and liabilities to reporting units, assignment of goodwill to reporting units and the determination of the fair value of the reporting units.  Management has determined Puget Energy has only one reporting unit.
	The goodwill recorded by Puget Energy represents the potential long-term return to the Company’s investors.  Goodwill is tested for impairment annually using a two-step process.  The first step compares the carrying amount of the reporting unit with its fair value, with a carrying value higher than fair value indicating potential impairment.  If the first step test fails, the second step is performed.  This would entail a full valuation of Puget Energy’s assets and liabilities and comparing the valuation to its carrying amounts, with the aggregate difference indicating the amount of impairment.  Goodwill of a reporting unit is required to be tested for impairment on an interim basis if an event occurs or circumstances change that would cause the fair value of a reporting unit to fall below its carrying amount.
	Puget Energy conducted its annual impairment test in 2014 using an October 1, 2014 measurement date.  The fair value of Puget Energy’s reporting unit was estimated using both discounted cash flow and market approach.  Such approaches are considered methodologies that market participants would use.  This analysis requires significant judgments, including estimation of future cash flows, which is dependent on internal forecasts, estimation of long-term rate of growth for Puget Energy business, estimation of the useful life over which cash flows will occur, the selection of utility holding companies determined to be comparable to Puget Energy and determination of an appropriate weighted-average cost of capital or discount rate.  The market approach estimates the fair value of the business based on market prices of stocks of comparable companies engaged in the same or similar lines of business.  In addition, indications of market value are estimated by deriving multiples of equity or invested capital to various measures of revenue, earnings or cash flow.  Changes in these estimates and/or assumptions could materially affect the determination of fair value and goodwill impairment of the reporting unit.  Based on the test performed, management has determined that there was no indication of impairment of Puget Energy’s goodwill as of October 1, 2014.  There were no known events or circumstances from the date of the assessment through December 31, 2014 that would impact management’s conclusion.
	Cash and Cash Equivalents
	Cash and cash equivalents consist of demand bank deposits and short-term highly liquid investments with original maturities of three months or less at the time of purchase.  The cash and cash equivalents balance at Puget Energy was $37.5 million and $44.3 million as of December 31, 2014 and 2013, respectively.  The 2014 and 2013 balance consisted of cash equivalents, which are reported at cost and approximate fair value, and were $1.8 million and $2.6 million, respectively.
	Materials and Supplies
	Materials and supplies are used primarily in the operation and maintenance of electric and natural gas distribution and transmission systems as well as spare parts for combustion turbines used for the generation of electricity.  Puget Energy and PSE record these items at weighted-average cost.
	Fuel and Gas Inventory
	Fuel and gas inventory is used in the generation of electricity and for future sales to the Company’s natural gas customers.  Fuel inventory consists of coal, diesel and natural gas used for generation.  Gas inventory consists of natural gas and Liquefied Natural Gas (LNG) held in storage for future sales.  Puget Energy and PSE record these items at the lower of cost or market value using the weighted-average cost method.
	Regulatory Assets and Liabilities
	PSE accounts for its regulated operations in accordance with ASC 980 “Regulated Operations” (ASC 980).  ASC 980 requires PSE to defer certain costs that would otherwise be charged to expense, if it is probable that future rates will permit recovery of such costs.  It similarly requires deferral of revenues or gains and losses that are expected to be returned to customers in the future.  Accounting under ASC 980 is appropriate as long as rates are established by or subject to approval by independent third-party regulators; rates are designed to recover the specific enterprise’s cost of service; and in view of demand for service, it is reasonable to assume that rates set at levels that will recover costs can be charged to and collected from customers.  In most cases, PSE classifies regulatory assets and liabilities as long-term due to the length of the amortization.  For further details regarding regulatory assets and liabilities, see Note 3.
	Allowance for Funds Used During Construction
	AFUDC represents the cost of both the debt and equity funds used to finance utility plant additions during the construction period.  The amount of AFUDC recorded in each accounting period varies depending principally upon the level of construction work in progress and the AFUDC rate used.  AFUDC is capitalized as a part of the cost of utility plant and is credited to interest expense and as a non-cash item to other income.  Cash inflow related to AFUDC does not occur until these charges are reflected in rates.
	The AFUDC rates authorized by the Washington Commission for natural gas and electric utility plant additions based on the effective dates are as follows:
	Effective Date	Washington Commission
		AFUDC Rates
	July 1, 2013 - present	7.77	%
	May 14, 2012 - June 30, 2013	7.8
	April 8, 2010 - May 13, 2012	8.1
	The Washington Commission authorized the Company to calculate AFUDC using its allowed rate of return.  To the extent amounts calculated using this rate exceed the AFUDC calculated rate using the Federal Energy Regulatory Commission (FERC) formula, PSE capitalizes the excess as a deferred asset, crediting other income.  The deferred asset is being amortized over the average useful life of PSE’s non-project electric utility plant which is approximately 30 years.
	Revenue Recognition
	Operating utility revenue is recognized when the basis of services is rendered, which includes estimated unbilled revenue, in accordance with ASC 605, “Revenue Recognition” (ASC 605).  PSE's estimate of unbilled revenue is based on a calculation using meter readings from its automated meter reading (AMR) system. The estimate calculates unbilled usage at the end of each month as the difference between the customer meter readings on the last day of the month and the last customer meter readings billed. The unbilled usage is then priced at published rates for each schedule to estimate the unbilled revenues by customer.
	The non-utility subsidiary recognizes revenue when services are performed or upon the sale of assets.  Revenue from retail sales is billed based on tariff rates approved by the Washington Commission.  Sales of Renewable Energy Credits (RECs) are deferred as a regulatory liability.
	Beginning July 1, 2013, PSE's electric and gas operations contain a revenue decoupling mechanism under which PSE's actual energy delivery revenues related to electric transmission and distribution, gas operations and general administrative costs are compared with authorized revenues allowed under the mechanism. Any differences are deferred to a regulatory asset for under recovery or regulatory liability for over recovery. Revenues associated with power costs under the PCA mechanism and PGA rates are excluded from the decoupling mechanism. The decoupling mechanism reduces earnings volatility, but does not materially affect the timing of cash flow due to the timing difference between the recognition of decoupling revenue and resulting impacts on rates.
	Allowance for Doubtful Accounts
	Allowance for doubtful accounts are provided for electric and natural gas customer accounts based upon a historical experience rate of write-offs of energy accounts receivable along with information on future economic outlook.  The allowance account is adjusted monthly for this experience rate.   The allowance account is maintained until either receipt of payment or the likelihood of collection is considered remote at which time the allowance account and corresponding receivable balance are written off.
	The Company’s allowance for doubtful accounts at December 31, 2014 and 2013 was $7.5 million and $7.4 million, respectively.
	Self-Insurance
	PSE is self-insured for storm damage and environmental contamination occurring on PSE-owned property.  In addition, PSE is required to meet a deductible for a portion of the risk associated with comprehensive liability, workers’ compensation claims and catastrophic property losses other than those which are storm related.  The Washington Commission has approved the deferral of certain uninsured qualifying storm damage costs that exceed $8.0 million which will be requested for collection in future rates.  Additionally, costs may only be deferred if the outage meets the Institute of Electrical and Electronics Engineers (IEEE) outage criteria for system average interruption duration index.
	Federal Income Taxes
	For presentation in Puget Energy and PSE’s separate financial statements, income taxes are allocated to the subsidiaries on the basis of separate company computations of tax, modified by allocating certain consolidated group limitations which are attributed to the separate company.  Taxes payable or receivable are settled with Puget Holdings.
	Natural Gas Off-System Sales and Capacity Release
	PSE contracts for firm natural gas supplies and holds firm transportation and storage capacity sufficient to meet the expected peak winter demand for natural gas by its firm customers.  Due to the variability in weather, winter peaking consumption of natural gas by most of its customers and other factors, PSE holds contractual rights to natural gas supplies and transportation and storage capacity in excess of its average annual requirements to serve firm customers on its distribution system.  For much of the year, there is excess capacity available for third-party natural gas sales, exchanges and capacity releases.  PSE sells excess natural gas supplies, enters into natural gas supply exchanges with third parties outside of its distribution area and releases to third parties excess interstate natural gas pipeline capacity and natural gas storage rights on a short-term basis to mitigate the costs of firm transportation and storage capacity for its core natural gas customers.  The proceeds from such activities, net of transactional costs, are accounted for as reductions in the cost of purchased natural gas and passed on to customers through the PGA mechanism, with no direct impact on net income. As a result, PSE nets the sales revenue and associated cost of sales for these transactions in purchased natural gas.
	Non-Core Gas Sales
	As part of the Company’s electric operations, PSE provides natural gas to its gas-fired generation facilities.  The projected volume of natural gas for power is relative to the price of natural gas.  Based on the market prices for natural gas, PSE may use the gas it has already purchased to generate power or PSE may sell the already purchased natural gas.  The net proceeds from selling natural gas, previously purchased for power generation, are accounted for in other electric operating revenue and are included in the PCA mechanism.
	Production Tax Credit
	Production Tax Credits (PTCs) represent federal income tax incentives available to taxpayers that generate energy from qualifying renewable sources.  PSE records the benefit of the PTCs as a regulatory liability until such time as PSE utilizes the tax credit on its tax return. Once utilized, PSE will pass the benefit to customers.
	Accounting for Derivatives
	ASC 815 requires that all contracts considered to be derivative instruments be recorded on the balance sheet at their fair value unless the contracts qualify for an exception.  PSE enters into derivative contracts to manage its energy resource portfolio and interest rate exposure including forward physical and financial contracts and swaps.  Some of PSE’s physical electric supply contracts qualify for the Normal Purchase Normal Sale (NPNS) exception to derivative accounting rules.  PSE may enter into financial fixed price contracts to economically hedge the variability of certain index-based contracts.  Those contracts that do not meet the NPNS exception are marked-to-market to current earnings in the statements of income, subject to deferral under ASC 980, for energy related derivatives due to the PCA mechanism and PGA mechanism.
	Puget Energy and PSE elected to de-designate all energy related derivative contracts previously recorded as cash flow hedges for the purpose of simplifying its financial reporting in 2009.  The contracts that were de-designated related to physical electric supply contracts and natural gas swap contracts used to fix the price of natural gas for electric generation.  For these contracts and for contracts initiated after such date, all mark-to-market adjustments are recognized through earnings.  The amount previously recorded in accumulated OCI is transferred to earnings in the same period or periods during which the hedged transaction affects earnings or sooner if management determines that the forecasted transaction is probable of not occurring.  As a result, the Company will continue to experience the earnings impact of these reversals from OCI in future periods. When these contracts are settled, the contract price becomes part of purchased electricity or electric generation fuel which becomes part of PSE’s PCA mechanism and the unrealized gain or loss is listed separately under energy costs, as it represents the non-rate treatment of energy costs.
	The Company may enter into swap instruments or other financial derivative instruments to manage the interest rate risk associated with its long-term debt financing and debt instruments.  As of December 31, 2014, Puget Energy has interest rate swap contracts outstanding related to its long-term debt.  For additional information, see Note 9 Accounting for Derivative Instruments and Hedging Activities.
	Fair Value Measurements of Derivatives
	ASC 820, “Fair Value Measurements and Disclosures” (ASC 820), defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price).  As permitted under ASC 820, the Company utilizes a mid-market pricing convention (the mid-point price between bid and ask prices) as a practical expedient for valuing the majority of its assets and liabilities measured and reported at fair value.  The Company utilizes market data or assumptions that market participants would use in pricing the asset or liability, including assumptions about risk and the risks inherent in the inputs to the valuation technique.  These inputs can be readily observable, market corroborated or generally unobservable.  The Company primarily applies the market approach for recurring fair value measurements as it believes that the approach is used by market participants for these types of assets and liabilities.  Accordingly, the Company utilizes valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs.
	The Company values derivative instruments based on daily quoted prices from an independent external pricing service.  When external quoted market prices are not available for derivative contracts, the Company uses a valuation model that uses volatility assumptions relating to future energy prices based on specific energy markets and utilizes externally available forward market price curves.  All derivative instruments are sensitive to market price fluctuations that can occur on a daily basis.  For additional information, see Note 10 Fair Value Measurements.
	Debt Related Costs
	Debt premiums, discounts, expenses and amounts received or incurred to settle hedges are amortized over the life of the related debt for the Company.  The premiums and costs associated with reacquired debt are deferred and amortized over the life of the related new issuance, in accordance with ratemaking treatment for PSE.
	Accumulated Other Comprehensive Income (Loss)
	The following tables set forth the components of the Company’s accumulated other comprehensive income (loss) at:
	Puget Energy	December 31,
(Dollars in Thousands)	2014			2013
Net unrealized loss on energy derivative instruments	$	(333	)	$	(705	)
Net unrealized loss on interest rate swaps	—			(94		)
Net unrealized loss and prior service cost on pension plans	(36,710		)	48,514
Total Puget Energy, net of tax	$	(37,043	)	$	47,715
Puget Sound Energy	December 31,
(Dollars in Thousands)	2014			2013
Net unrealized loss on energy derivative instruments	$	(686	)	$	(2,027	)
Net unrealized loss on treasury interest rate swaps	(5,990		)	(6,307		)
Net unrealized loss and prior service cost on pension plans	(164,281		)	(87,405		)
Total PSE, net of tax	$	(170,957	)	$	(95,739	)

New_Accounting_Pronouncements

New Accounting Pronouncements	12 Months Ended
	Dec. 31, 2014
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
New Accounting Pronouncements	New Accounting Pronouncements
	Income Statement
	In May 2014, the FASB issued Accounting Standards Update (ASU) No. 2014-09, "Revenue from Contracts with Customers (Topic 606)", that outlines a single comprehensive model for use in accounting for revenue arising from contracts with customers and supersedes most current revenue recognition guidance, including industry-specific guidance. The ASU is based on the principle that an entity should recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The ASU also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to fulfill a contract.
	ASU 2014-09 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2016.  Early adoption of the ASU is not permitted.  Entities have the option of using either a full retrospective or a modified retrospective approach for the adoption of the new standard.  The Company initiated a steering committee and project team to evaluate the impact of this standard, update any policies and procedures that may be affected and implement the new revenue recognition guidance. At this time, the Company cannot determine the impact this standard will have on its consolidated financial statements.
	Extraordinary and Unusual Items
	In January 2015, the FASB issued ASU 2015-01, "Income Statement - Extraordinary and Unusual Items (Subtopic 225-20): Simplifying Income Statement Presentation by Eliminating the Concept of Extraordinary Items." As part of FASB's initiative to reduce complexity in accounting standards, it issued ASU 2015-01, which eliminates from GAAP the concept of extraordinary items. Currently, Subtopic 225-20 requires an entity to separately classify, present and disclose extraordinary events and transactions. ASU 2015-01 will align GAAP income statement presentation guidance with International Accounting Standards 1, Presentation of Financial Statements, which prohibits the presentation and disclosure of extraordinary items.
	ASU 2015-01 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015. The Company is permitted to apply amendments prospectively or retrospectively to all prior periods presented in the financial statements. Early adoption is permitted, provided that the guidance is applied from the beginning of the fiscal year of adoption. At this time, the Company doesn't expect this standard to have a material effect on the Company's financial position or results of operations.

Regulation_and_Rates

Regulation and Rates	12 Months Ended
	Dec. 31, 2014
Regulated Operations [Abstract]
Regulation and Rates	Regulation and Rates
	Regulatory Assets and Liabilities
	ASC 980 requires PSE to defer certain costs that would otherwise be charged to expense, if it is probable that future rates will permit recovery of such costs.  It similarly requires deferral of revenues or gains and losses that are expected to be returned to customers in the future.
	Below is a chart with the allowed return on the net regulatory assets and liabilities and the associated time periods:
	Period	Rate of Return	After-Tax Return
	July 1, 2013 - present	7.77%	6.69%
	May 14, 2012 - June 30, 2013	7.8	6.71
	April 8, 2010 - May 13, 2012	8.1	6.9
	The net regulatory assets and liabilities at December 31, 2014 and 2013 included the following:
	Puget Sound Energy	Remaining Amortization Period	December 31,
	(Dollars in Thousands)		2014			2013
	PGA deferral of unrealized losses on derivative instruments	(a)	$	69,280		$	27,555
	Chelan PUD contract initiation	16.8 Years	119,316			126,404
	Storm damage costs electric	1 to 4 years	118,824			116,328
	Environmental remediation	(a)	66,018			57,342
	Baker Dam licensing operating and maintenance costs	44 years	61,577			57,270
	Snoqualmie licensing operating and maintenance costs	30 years	9,202			10,881
	Colstrip common property	9.5 years	6,764			7,479
	Deferred income taxes	(a)	94,913			146,350
	Deferred Washington Commission AFUDC	35 years	53,709			55,495
	Energy conservation costs	1 to 2 years	42,374			35,987
	Unamortized loss on reacquired debt	1 to 21.5 years	35,667			37,832
	White River relicensing and other costs	17.9 years	26,685			28,190
	Mint Farm ownership and operating costs	10.3 years	20,320			22,320
	Investment in Bonneville Exchange power contract	2.5 years	8,816			12,343
	Ferndale	4.8 years	19,232			22,811
	Lower Snake River	1.3 to 22.3 years	86,275			92,924
	Snoqualmie	3.8 years	6,798			8,009
	Property tax tracker	Less than 2 years	32,253			22,134
	PGA receivable	1 year	21,073			—
	PCA mechanism	(a)	4,623			—
	Electron unrecovered loss	4 years	14,008			—
	Decoupling under-collection	Less than 2 years	55,363			—
	Various other regulatory assets	Varies	14,312			8,078
	Total PSE regulatory assets		$	987,402		$	895,732
	Cost of removal	(b)	$	(313,088	)	$	(269,536	)
	Production tax credits	(c)	(93,616		)	(93,618		)
	PGA payable	1 year	—			(5,938		)
	PCA mechanism	(a)	—			(5,345		)
	Decoupling over-collection	Less than 2 years	(12,582		)	(20,535		)
	Summit purchase option buy-out	5.8 years	(9,188		)	(10,763		)
	Deferred gain on Jefferson County sale	Less than 1 year	(4,731		)	(60,844		)
	Deferred credit on Biogas sale	1 year	(1,445		)	(10,908		)
	Deferred credit on gas pipeline capacity	Varies up to 3.8 years	(3,564		)	(4,508		)
	Renewable energy credits	1 year	(2,383		)	(5,820		)
	Treasury grants	5 to 44 years	(180,496		)	(203,889		)
	Deferral of treasury grant amortization	Less than 4 years	(8,197		)	—
	Various other regulatory liabilities	Up to 4 years	(6,092		)	(5,755		)
	Total PSE regulatory liabilities		$	(635,382	)	$	(697,459	)
	PSE net regulatory assets (liabilities)		$	352,020		$	198,273
	_______________
	(a)	Amortization periods vary depending on timing of underlying transactions or awaiting regulatory approval in a future Washington Commission rate proceeding.
	(b)	The balance is dependent upon the cost of removal of underlying assets and the life of utility plant.
	(c)	Amortization will begin once PTCs are utilized by PSE on its tax return.
	Puget Energy	Remaining Amortization Period	December 31,
	(Dollars in Thousands)		2014			2013
	Total PSE regulatory assets	(a)	$	987,402		$	895,732
	Puget Energy acquisition adjustments:
	Regulatory assets related to power contracts	1 to 22 years	29,816			33,753
	Various other regulatory assets	Varies	561			517
	Total Puget Energy regulatory assets		$	1,017,779		$	930,002
	Total PSE regulatory liabilities	(a)	$	(635,382	)	$	(697,459	)
	Puget Energy acquisition adjustments:
	Regulatory liabilities related to power contracts	1 to 37 years	(391,389		)	(443,065		)
Various other regulatory liabilities	Varies	(2,820		)	(2,884		)
Total Puget Energy regulatory liabilities		$	(1,029,591	)	$	(1,143,408	)
Puget Energy net regulatory asset (liabilities)		$	(11,812	)	$	(213,406	)
_______________
(a)	Puget Energy’s regulatory assets and liabilities include purchase accounting adjustments under ASC 805 as a result of the merger.
If the Company determines that it no longer meets the criteria for continued application of ASC 980, the Company would be required to write off its regulatory assets and liabilities related to those operations not meeting ASC 980 requirements.  Discontinuation of ASC 980 could have a material impact on the Company’s financial statements.
In accordance with guidance provided by ASC 410, “Asset Retirement and Environmental Obligations,” PSE reclassified from accumulated depreciation to a regulatory liability $313.1 million and $269.5 million in 2014 and 2013, respectively, for the cost of removal of utility plant.  These amounts are collected from PSE’s customers through depreciation rates.
Electric Regulation and Rates
Storm Damage Deferral Accounting
The Washington Commission issued a general rate case order that defined deferrable catastrophic/extraordinary losses and provided that costs in excess of $8.0 million annually may be deferred for qualifying storm damage costs that meet the modified IEEE outage criteria for system average interruption duration index. In 2014 and 2013, PSE incurred $29.7 million and $9.4 million, respectively, in storm-related electric transmission and distribution system restoration costs, of which $18.0 million was deferred in 2014 and no amount was deferred in 2013.
Power Cost Only Rate Case
Power Cost Only Rate Case (PCORC), a limited-scope proceeding, was approved in 2002 by the Washington Commission to periodically reset power cost rates.  In addition to providing the opportunity to reset all power costs, the PCORC proceeding also provides for timely review of new resource acquisition costs and inclusion of such costs in rates at the time the new resource goes into service.  To achieve this objective, the Washington Commission has used an expedited six-month PCORC decision timeline rather than the statutory 11-month timeline for a general rate case.
On October 23, 2013, the Washington Commission approved an update on the Company's PCORC, effective November 1, 2013, which reflected decreases in the overall normalized power supply costs. This resulted in an estimated revenue decrease of $10.5 million or 0.5% annually.
On November 3, 2014 the Washington Commission issued an order on the settlement of the PCORC which PSE filed on May 23, 2014. The original filing proposed a decrease of $9.6 million (or an average of approximately 0.5%) in the Company's overall power supply costs. PSE filed joint testimony supporting a settlement stipulation. Customer rates decreased by approximately $19.4 million or 0.90% annually, as a result of the settlement, effective December 1, 2014.
Electric Rate Case
On April 24, 2014, the Washington Commission approved PSE’s request to change rates under its electric and natural gas decoupling mechanism, effective May 1, 2014.  The rate change incorporated the effects of an increase to the allowed delivery revenue per customer as well as true-ups to the rate from the prior year.  This represents a rate increase for electric of $10.6 million, or 0.5% annually, and a rate decrease for natural gas of $1.0 million, or 0.1% annually.
On April 24, 2014, the Washington Commission approved PSE’s request to change rates under its electric and natural gas property tax tracker mechanism, effective May 1, 2014.  The rate change incorporated the effects of an increase in the amount of property taxes paid as well as true-ups to the rate from the prior year.  This represents a rate increase for electric of $11.0 million, or 0.5% annually, and a rate increase for natural gas of $5.6 million, or 0.6% annually.
On April 24, 2014, the Washington Commission also approved PSE’s request to change rates under its electric and natural gas conservation riders, effective May 1, 2014.  The rate change incorporated the effects of changes in the annual conservation budgets as well as true-ups to the rate from the prior year.  The rate change represents a rate increase for electric of $12.2 million, or 0.5% annually, and a rate increase for natural gas of $0.3 million.
On November 3, 2014 the Washington Commission approved PSE's 2014 PCORC. The original filing proposed a decrease of $9.6 million (or an average of approximately 0.5%) in the Company's overall power supply costs with an effective date of December 1, 2014. PSE filed joint testimony supporting a settlement stipulation. Customer rates decreased by approximately $19.4 million or 0.90% as a result of the settlement, effective December 1, 2014.
On June 25, 2013, the Washington Commission approved PSE's electric and natural gas decoupling mechanism and expedited rate filing (ERF) tariff filings, effective July 1, 2013. The estimated revenue impact of the decoupling mechanism for electric is an increase of $21.4 million, or 1.0% annually. The estimated revenue impact of the ERF filings for electric is an increase of $30.7 million, or 1.5% annually. In its order, the Washington Commission approved a weighted cost of capital of 7.8% and a capital structure that included 48.0% common equity with a return on equity of 9.8%. Subsequently, certain parties to this proceeding petitioned the Washington Commission to reconsider the order. On December 13, 2013, the Washington Commission approved the settlement agreements for rates effective January 1, 2014. These settlement agreements do not materially change the revenues originally approved in June 2013.
On July 24, 2013, the Public Counsel Division of the Washington State Attorney General's Office (Public Counsel) and the Industrial Customers of Northwest Utilities (ICNU) each filed a petition in Thurston County Superior Court (the Court) seeking judicial reviews of various aspects of the Washington Commission's ERF and decoupling mechanism final order. The parties' petition argues that the order violates various procedural and substantive requirements of the Washington Administrative Procedure Act, and so requests that it be vacated and that the matter be remanded to the Washington Commission. Oral arguments regarding this matter were held on May 9, 2014. On June 25, 2014, the court issued a letter decision in which it affirmed the attrition adjustment (escalating factors referred to as the K-Factor) and the Washington Commission's decision not to consider the case as a general rate case, but reversed and remanded the cost of equity for further adjudication consistent with the court's decision. As a result, there will be evidentiary proceedings regarding Return on Equity (ROE) in February 2015 with an order anticipated in the first half of 2015.
On May 7, 2012, the Washington Commission issued its order in PSE's electric general rate case filed in June 2011, approving a general rate increase for electric customers of $63.3 million or 3.2% annually. The rate increases for electric customers became effective May 14, 2012. In its order, the Washington Commission approved a weighted cost of capital of 7.8% and a capital structure that included 48.0% common equity with a return on equity of 9.8%. PSE's requested treatment of the prepayments made to Bonneville Power Administration (BPA), filed in May 2010, was approved in the order. The final order rejected PSE's proposed conservation savings adjustment. Finally, a new rate rider for RECs was proposed by settlement of electric parties and approved by the Washington Commission in the final order.
The following table sets forth electric rate adjustments approved by the Washington Commission and the corresponding impact on PSE’s revenue based on the effective dates:
Type of Rate	Effective Date	Average	Increase (Decrease)
Adjustment		Percentage	in Revenue
		Increase (Decrease)	(Dollars in Millions)
		in Rates
PCORC	1-Dec-14	-0.90%	($19.40)
Conservation Rider	1-May-14	0.50%	12.2
Decoupling Rate Filing	1-May-14	0.5	10.6
Property Tax Tracker	1-May-14	0.5	11
PCORC	1-Nov-13	0.5	10.5
Decoupling Rate Filing	1-Jul-13	1	21.4
Expedited Rate Filing	1-Jul-13	1.5	30.7
Electric General Rate Case	14-May-12	3.2	63.3
In addition, PSE will be increasing the allowed delivery revenue per customer under the decoupling filing by 3.0% for electric customers on January 1 of each year until the conclusion of PSE's next general rate case.
Accounting Orders and Petitions
On November 27, 2013, the Washington Commission issued an order authorizing PSE to provide the net proceeds from the sale of natural gas supply produced from a landfill-gas recovery project in King County (Biogas) prior to October 31, 2013 as a bill credit to customers over a one-year period in its RECs adjusting price schedule which became effective January 1, 2014.  Additionally, the Washington Commission order authorized that all net proceeds from Biogas produced after October 31, 2013 plus the internal labor needed to obtain the net proceeds is reflected as a PSE below-the-line item (i.e., not included in the revenues and expenses considered when setting electric customer rates) and excluded from utility operations.
PSE completed the sale of its electric infrastructure assets located in Jefferson County and the transition of electrical services in the county to JPUD on March 31, 2013.  The proceeds from the sale exceeded the transferred assets' net carrying value of $46.7 million resulting in a pre-tax gain of approximately $60.0 million.  In its 2010 order on the subject, the Washington Commission stated that PSE must file an accounting and ratemaking petition with the Washington Commission to determine how this gain will be allocated between customers and shareholders.  As a result, the gain was deferred and recorded as a regulatory liability pending the Washington Commission's determination of the accounting and ratemaking treatment.  On October 31, 2013, PSE filed an accounting petition for a Washington Commission order that would authorize PSE to retain the gain of $45.0 million and return $15.0 million to its remaining customers over a period of 48 months.  On March 28, 2014, intervenors filed response testimonies containing their respective proposals for allocation of the gain, which included a proposal of up to $57.0 million to customers and $3.0 million to PSE. A final order was rendered on September 11, 2014 authorizing PSE to retain $7.5 million of the gain and return $52.7 million to customers. The customer portion is booked to a regulatory liability account in other current liabilities and accruing interest at PSE's after-tax rate of return. PSE and the parties to the case filed a joint motion to amend the final order to allow for the customer portion to be paid to customers through a bill credit in the month of December 2014. The Commission granted the joint motion on October 1, 2014.
PCA Mechanism
In 2002, the Washington Commission approved a PCA mechanism that provides for a rate adjustment process if PSE’s costs to provide customers’ electricity vary from a baseline power cost rate established in a rate proceeding. All significant variable power supply cost variables (hydroelectric and wind generation, market price for purchased power and surplus power, natural gas and coal fuel price, generation unit forced outage risk and transmission cost) are included in the PCA mechanism.
The PCA mechanism apportions increases or decreases in power costs, on a calendar year basis, between PSE and its customers on a graduated scale.
The graduated scale is as follows:
Annual Power Cost Variability	Customers’ Share	Company’s Share
+/- $20 million	0%	100%
+/- $20 million - $40 million	50%	50%
+/- $40 million - $120 million	90%	10%
+/- $120 + million	95%	5%
Treasury Grant
Section 1603 of the American Recovery and Reinvestment Tax Act of 2009 (Section 1603) authorizes the United States Department of the Treasury (U.S. Treasury) to make grants (Treasury Grants) to taxpayers who place specified energy property in service provided certain conditions are met.   Section 1603 precludes a recipient from claiming PTCs on property for which a grant is claimed.
PSE received two treasury grants with a total amount of $107.9 million, related to Baker and Snoqualmie hydro facilities. These grants have been accounted as a reduction to utility plant and will be amortized over the life of the plant based on the Washington Commission authorization.
The Wild Horse Wind Project (Wild Horse) expansion facility was placed into service on November 9, 2009. The capacity of the Wild Horse facility was expanded from 229 megawatts (MW) to 273 MW through the addition of wind turbines.  In February 2010, the U.S. Treasury approved a Treasury Grant of $28.7 million. The 343 MW Lower Snake River facility was placed into service on February 29, 2012. In December 2012, the U.S. Treasury approved a Treasury Grant of $205.3 million.
On February 29, 2012, PSE filed proposed tariff revisions, with stated effective dates of April 1, 2012, and subsequently revised by filing on March 29, 2012 with stated effective dates of June 1, 2012, to pass-through $2.4 million in interest on the unamortized balance of the Wild Horse Expansion Treasury Grant.  On June 26, 2012, the Washington Commission approved PSE's methods and calculations and new rates became effective on July 3, 2012.
On January 31, 2013, the Washington Commission approved a rate change to the PSE's Federal Incentive Tracker tariff, effective February 1, 2013, which incorporated the effects of the Treasury Grant related to the Lower Snake River wind generation project and keeping the ten year amortization period and inclusion of interest on the unamortized balance of the grants. The rate change passed through 11 months of amortization for both grants to eligible customers over 11 months beginning February 1, 2013. Of the total credit, $34.6 million represents the pass-back of grant amortization and $23.8 million represents the pass through of interest. This represents an overall average rate decrease of 2.8%.
On December 27, 2013, the Washington Commission approved the annual true-up and rate filing to the PSE's Federal Incentive Tracker tariff, effective January 1, 2014. The true-up filing resulted in a total credit of $58.5 million to be passed back to eligible customers over the twelve months beginning January 1, 2014.  Of the total credit, $37.8 million represents the pass-back of grant amortization and $20.6 million represents the pass through of interest, in addition to a minor true-up associated with the 2013 rate period.  This filing represents an overall average rate increase of 0.3%.
Gas Regulation and Rates
Gas General Rate Cases and Other Filings Affecting Rates
On May 7, 2012, the Washington Commission issued its order in PSE's natural gas general rate case filed in June 2011, approving a general rate increase for natural gas customers of $13.4 million, or 1.3% annually. The rate increases for natural gas customers became effective May 14, 2012. In its order, the Washington Commission approved a weighted cost of capital of 7.8% and a capital structure that included 48.0% common equity with a return on equity of 9.8%.
On June 1, 2012, PSE filed with the Washington Commission a petition seeking an Accounting Order authorizing PSE to change the existing natural gas conservation tracker mechanism into a rider mechanism to be consistent with the electric conservation program recovery. The accounting petition requested the ability to recover the costs associated with the Company's current gas conservation programs via transfers from amounts deferred for the over-recovery of commodity costs in the Company's PGA mechanism. The Commission granted PSE's accounting petition on June 28, 2012. The approved accounting petition resulted in an increase to gas conservation revenues of $6.9 million and an increase to conservation amortization expense of $6.6 million.
On June 25, 2013, the Washington Commission approved PSE's electric and natural gas decoupling mechanism and ERF tariff filings, effective July 1, 2013. The estimated revenue impact of the decoupling mechanism for natural gas is an increase of $10.8 million, or 1.1% annually. The estimated revenue impact of the ERF filings for natural gas is a decrease of $2.0 million, or a decrease of 0.2% annually. In its order, the Washington Commission approved a weighted cost of capital of 7.8% and a capital structure that included 48.0% common equity with a return on equity of 9.8%.
Subsequently, certain parties to this proceeding petitioned the Washington Commission to reconsider the order. On December 13, 2013, the Washington Commission approved a series of settlement agreements for rates effective January 1, 2014. These settlement agreements do not materially change the revenues originally approved in June 2013. As a result, certain high volume natural gas industrial customers rate schedules are excluded from the decoupling mechanism and will be subject to certain effects of abnormal weather, conservation impacts and changes in customer usage patterns.
On July 24, 2013, the Public Counsel Division of the Washington State Attorney General's Office (Public Counsel) and the Industrial Customers of Northwest Utilities (ICNU) each filed a petition in Thurston County Superior Court (the Court) seeking judicial review of various aspects of the Washington Commission's ERF and decoupling mechanism final order. The parties' petition argues that the order violates various procedural and substantive requirements of the Washington Administrative Procedure Act, and so requests that it be vacated and that the matter be remanded to the Washington Commission. Oral arguments regarding this matter were held on May 9, 2014. On June 25, 2014, the court issued a letter decision in which it affirmed the attrition adjustment K-Factor and the Washington Commission's decision not to consider the case as a general rate case, but reversed and remanded the cost of equity for further adjudication consistent with the court's decision. As a result, there will be evidentiary proceedings regarding ROE in February 2015 with an order anticipated in the first half of 2015.
Purchased Gas Adjustment
PSE has a PGA mechanism in retail natural gas rates to recover variations in natural gas supply and transportation costs.  Variations in natural gas rates are passed through to customers; therefore, PSE’s net income is not affected by such variations.  Changes in the PGA rates affect PSE’s revenue, but do not impact net operating income as the changes to revenue are offset by increased or decreased purchased gas and gas transportation costs.
On October 30, 2014, the Washington Commission approved the PGA natural gas tariff which proposed to reflect changes in wholesale gas and pipeline transportation costs and changes in deferral amortization rates. The impact of PGA rates is an annual revenue decrease of $23.3 million , or 2.5% annually, with no impact on net operating income.
On October 30, 2013, the Washington Commission approved PSE's PGA natural gas tariff, effective on November 1, 2013, which reflected changes in wholesale gas and pipeline transportation costs and changes in deferral amortization rates. The estimated revenue impact of the approved change is an increase of $4.0 million, or 0.4% annually, with no impact on net operating income.
On October 31, 2012, the Washington Commission approved PSE's PGA natural gas tariff filing and allowed the rates to go into effect on November 1, 2012 on a temporary basis subject to revision. The rates resulted in a decrease to the rates charged to customers under the PGA. On May 1, 2013, the Washington Commission approved the proposed rates and allowed them to be made permanent. The estimated revenue impact of the approved change is a decrease of $77.0 million, or 7.7% annually, with no impact on net operating income.
The following table sets forth natural gas rate adjustments that were approved by the Washington Commission and the corresponding impact to PSE’s annual revenue based on the effective dates:
Type of Rate	Effective Date	Average	Annual
Adjustment		Percentage	Increase (Decrease)
		Increase (Decrease)	in Revenue
		in Rates	(Dollars in Millions)
Purchased Gas Adjustment	1-Nov-14	-2.50%	($23.30)
Decoupling Rate Filing	1-May-14	-0.1	-1
Purchased Gas Adjustment	1-Nov-13	0.4	4
Decoupling Rate Filing	1-Jul-13	1.1	10.8
Expedited Rate Filing	1-Jul-13	-0.2	-2
Purchased Gas Adjustment	1-Nov-12	-7.7	-77
Natural Gas General Rate Case	14-May-12	1.3	13.4
Purchased Gas Adjustment	1-Nov-11	-4.3	-43.5
Natural Gas General Tariff Adjustment	1-Apr-11	1.8	19
In addition, PSE will be increasing the allowed delivery revenue per customer under the decoupling filing by 2.2% for natural gas customers on January 1 of each year until the conclusion of PSE's next general rate case.
Environmental Remediation
The Company is subject to environmental laws and regulations by the federal, state and local authorities and is required to undertake certain environmental investigative and remedial efforts as a result of these laws and regulations.  The Company has been named by the Environmental Protection Agency (EPA), the Washington State Department of Ecology and/or other third parties as potentially responsible at several contaminated sites and manufactured gas plant sites.  PSE has implemented an ongoing program to test, replace and remediate certain underground storage tanks (UST) as required by federal and state laws.  The UST replacement component of this effort is finished, but PSE continues its work remediating and/or monitoring relevant sites.  During 1992, the Washington Commission issued orders regarding the treatment of costs incurred by the Company for certain sites under its environmental remediation program.  The orders authorize the Company to accumulate and defer prudently incurred cleanup costs paid to third parties for recovery in rates established in future rate proceedings, subject to Washington Commission review.  The Washington Commission consolidated the gas and electric methodological approaches to remediation and deferred accounting in an order issued October 8, 2008.  Per the guidance of ASC 450, “Contingencies,” the Company reviews its estimated future obligations and will record adjustments, if any, on a quarterly basis.  Management believes it is probable and reasonably estimable that the impact of the potential outcomes of disputes with certain property owners and other potentially responsible parties will result in environmental remediation costs of $35.4 million for gas and $5.7 million for electric.  The Company believes a significant portion of its past and future environmental remediation costs are recoverable from insurance companies, from third parties or from customers under a Washington Commission order.  The Company is also subject to cost-sharing agreements with third parties regarding environmental remediation projects in Seattle, Washington and Bellingham, Washington. The Company has taken the lead for both projects. As of December 31, 2014, the Company’s share of future remediation costs is estimated to be approximately $25.2 million. The Company's deferred electric environmental costs are $13.4 million, $12.3 million, and $10.9 million at December 31, 2014, 2013 and 2012, respectively, net of insurance proceeds. The Company's deferred natural gas environmental costs are $52.6 million, $45.1 million, and $66.4 million at December 31, 2014, 2013 and 2012, respectively, net of insurance proceeds.

Dividend_Payment_Restrictions

Dividend Payment Restrictions	12 Months Ended
	Dec. 31, 2014
Dividend Payment Restrictions [Abstract]
Dividend Payment Restrictions	Dividend Payment Restrictions
	The payment of dividends by PSE to Puget Energy is restricted by provisions of certain covenants applicable to long-term debt contained in PSE’s electric and natural gas mortgage indentures.  At December 31, 2014, approximately $438.4 million of unrestricted retained earnings was available for the payment of dividends under the most restrictive mortgage indenture covenant.
	Beginning February 6, 2009, pursuant to the terms of the Washington Commission merger order, PSE may not declare or pay dividends if PSE’s common equity ratio, calculated on a regulatory basis, is 44.0% or below except to the extent a lower equity ratio is ordered by the Washington Commission.  Also, pursuant to the merger order, PSE may not declare or make any distribution unless on the date of distribution PSE’s corporate credit/issuer rating is investment grade, or, if its credit ratings are below investment grade, PSE’s ratio of Adjusted Earnings Before Interest, Tax, Depreciation and Amortization (EBITDA) to interest expense for the most recently ended four fiscal quarter periods prior to such date is equal to or greater than 3 to one.  The common equity ratio, calculated on a regulatory basis, was 47.7% at December 31, 2014, and the EBITDA to interest expense was 4.3 to one for the twelve months then ended.
	PSE’s ability to pay dividends is also limited by the terms of its credit facilities, pursuant to which PSE is not permitted to pay dividends during any Event of Default (as defined in the facilities), or if the payment of dividends would result in an Event of Default, such as failure to comply with certain financial covenants.
	Puget Energy’s ability to pay dividends is also limited by the merger order issued by the Washington Commission.  Pursuant to the merger order, Puget Energy may not declare or make a distribution unless on such date Puget Energy’s ratio of consolidated EBITDA to consolidated interest expense for the four most recently ended fiscal quarters prior to such date is equal to or greater than 2 to one.   Puget Energy's EBITDA to interest expense was 3.1 to one for the twelve months ended December 31, 2014.
	At December 31, 2014, the Company was in compliance with all applicable covenants, including those pertaining to the payment of dividends.

Utility_Plant

Utility Plant	12 Months Ended
	Dec. 31, 2014
Utility Plant [Abstract]
Utility Plant	Utility Plant
			Puget Energy						Puget Sound Energy
	Utility Plant	Estimated	At December 31,						At December 31,
		Useful Life
	(Dollars In Thousands)	(Years)	2014			2013			2014			2013
	Electric, gas and common utility plant classified by prescribed accounts :
	Distribution plant	Oct-50	$	4,748,988		$	4,448,451		$	6,417,551		$	6,127,732
	Production plant	25-125	2,973,853			2,966,223			3,907,224			3,948,270
	Transmission plant	45-65	1,189,296			1,043,605			1,306,009			1,162,929
	General plant	May-35	481,116			504,965			553,130			599,156
	Intangible plant (including capitalized software)	Mar-50	311,959			316,614			304,135			309,972
	Plant acquisition adjustment	30-Jul	242,826			242,826			282,792			282,792
	Underground storage	25-60	28,859			27,857			42,494			41,501
	Liquefied natural gas storage	25-45	12,628			12,622			14,498			14,492
	Plant held for future use	NA	54,996			28,742			55,148			28,895
	Recoverable Cushion Gas	NA	8,655			8,655			8,655			8,655
	Plant not classified	1-100	91,519			124,589			91,519			124,589
	Grant	NA	(105,659		)	—			(105,659		)	—
	Capital leases, net of accumulated amortization 1	5	9,473			17,051			9,473			17,051
	Less: accumulated provision for depreciation		(1,611,220		)	(1,373,178		)	(4,449,680		)	(4,297,012		)
	Subtotal		$	8,437,289		$	8,369,022		$	8,437,289		$	8,369,022
	Construction work in progress	NA	239,690			310,318			239,690			310,318
	Net utility plant		$	8,676,979		$	8,679,340		$	8,676,979		$	8,679,340
	_______________
	1	Accumulated amortization of capital leases at Puget Energy was $28.4 million in 2014 and $20.8 million in 2013.  Accumulated amortization of capital leases at PSE was $28.4 million in 2014 and $20.8 million in 2013.
	Jointly owned generating plant service costs are included in utility plant service cost at the Company's ownership share.  The following table indicates the Company’s percentage ownership and the extent of the Company’s investment in jointly owned generating plants in service at December 31, 2014.  These amounts are also included in the Utility Plant table above.
					Puget Energy’s						Puget Sound Energy’s
					Share						Share
	Jointly Owned Generating Plants	Energy Source (Fuel)	Company’s Ownership Share		Plant in Service at Cost			Accumulated Depreciation			Plant in Service at Cost			Accumulated Depreciation
	(Dollars in Thousands)
	Colstrip Units 1 & 2	Coal	50	%	$	158,516		$	(12,047	)	$	293,103		$	(146,635	)
	Colstrip Units 3 & 4	Coal	25	%	234,787			(28,763		)	509,619			(303,594		)
	Colstrip Units 1 – 4 Common Facilities 1	Coal	various		83			(21		)	252			(189		)
	Frederickson 1	Gas	49.85	%	61,771			(5,750		)	70,719			(14,698		)
	Jackson Prairie	Gas Storage	33.34	%	28,185			(4,099		)	42,494			(18,409		)
	_______________
	1 The Company's ownership is 50% for Colstrip 1&2 and 25% for Colstrip Units 3 &4.
	As of December 31, 2014, there are no new Asset Retirement Obligations (ARO) in 2014 and $0.4 million in 2013.
	The following table describes all changes to the Company’s ARO liability:
		At December 31,
	(Dollars in Thousands)	2014			2013
	Asset retirement obligation at beginning of period	$	48,687		$	45,496
	New asset retirement obligation recognized in the period	—			350
	Liability settled in the period	(602		)	(1,188		)
	Revisions in estimated cash flows	(480		)	2,769
	Accretion expense	1,304			1,260
	Asset retirement obligation at end of period	$	48,909		$	48,687
	The Company has identified the following obligations, as defined by ASC 410, “Asset Retirement and Environmental Obligations,” which were not recognized because the liability for these assets cannot be reasonably estimated at December 31, 2014 due to:
	•	A legal obligation under Federal Dangerous Waste Regulations to dispose of asbestos-containing material in facilities that are not scheduled for remodeling, demolition or sales. The disposal cost related to these facilities could not be measured since the retirement date is indeterminable; therefore, the liability cannot be reasonably estimated;
	•	An obligation under Washington state law to decommission the wells at the Jackson Prairie natural gas storage facility upon termination of the project.  Since the project is expected to continue as long as the Northwest pipeline continues to operate, the liability cannot be reasonably estimated;
	•	An obligation to pay its share of decommissioning costs at the end of the functional life of the major transmission lines.  The major transmission lines are expected to be used indefinitely; therefore, the liability cannot be reasonably estimated.
	•	A legal obligation under Washington state environmental laws to remove and properly dispose of certain under and above ground fuel storage tanks.  The disposal costs related to under and above ground storage tanks could not be measured since the retirement date is indeterminable; therefore, the liability cannot be reasonably estimated;
	•	An obligation to pay decommissioning costs at the end of utility service franchise agreements to restore the surface of the franchise area. The decommissioning costs related to facilities at the franchise area could not be measured since the decommissioning date is indeterminable; therefore, the liability cannot be reasonably estimated; and
	•	A potential legal obligation may arise upon the expiration of an existing FERC hydropower license if FERC orders the project to be decommissioned, although PSE contends that FERC does not have such authority.  Given the value of ongoing generation, flood control and other benefits provided by these projects, PSE believes that the potential for decommissioning is remote and cannot be reasonably estimated.

LongTerm_Debt

Long-Term Debt	12 Months Ended
	Dec. 31, 2014
Long-term Debt, Unclassified [Abstract]
Long-term Debt	(6)  Long-Term Debt
	(Dollars in Thousands)			At December 31,
	Series	Type	Due	2014			2013
	Puget Sound Energy:
	7.35%	First Mortgage Bond	2015	$	10,000		$	10,000
	7.36%	First Mortgage Bond	2015	2,000			2,000
	5.20%	Senior Secured Note	2015	150,000			150,000
	6.75%	Senior Secured Note	2016	250,000			250,000
	5.50%	Promissory Note 1	2017	2,412			2,412
	6.74%	Senior Secured Note	2018	200,000			200,000
	7.15%	First Mortgage Bond	2025	15,000			15,000
	7.20%	First Mortgage Bond	2025	2,000			2,000
	7.02%	Senior Secured Note	2027	300,000			300,000
	7.00%	Senior Secured Note	2029	100,000			100,000
	3.90%	Pollution Control Bond	2031	138,460			138,460
	4.00%	Pollution Control Bond	2031	23,400			23,400
	5.48%	Senior Secured Note	2035	250,000			250,000
	6.72%	Senior Secured Note	2036	250,000			250,000
	6.27%	Senior Secured Note	2037	300,000			300,000
	5.76%	Senior Secured Note	2039	350,000			350,000
	5.80%	Senior Secured Note	2040	325,000			325,000
	5.76%	Senior Secured Note	2040	250,000			250,000
	4.43%	Senior Secured Note	2041	250,000			250,000
	5.64%	Senior Secured Note	2041	300,000			300,000
	4.70%	Senior Secured Note	2051	45,000			45,000
	6.97%	Junior Subordinated Note	2067	250,000			250,000
		Unamortized discount on senior notes		(13		)	(14		)
	PSE long-term debt			$	3,763,259		$	3,763,258
	Puget Energy:
		Fair value adjustment of PSE long-term debt		$	(218,619	)	$	(229,746	)
		Credit Facility	2017	—			299,000
		Term-Loan	2016	100,000			—
		Term-Loan	2017	100,000			—
		Term-Loan	2016	99,000			—
	6.50%	Senior Secured Note	2020	450,000			450,000
	6.00%	Senior Secured Note	2021	500,000			500,000
	5.63%	Senior Secured Note	2022	450,000			450,000
		Unamortized discount on senior notes		(32		)	(36		)
	Total Puget Energy long-term debt			$	5,243,608		$	5,232,476
	____________
	1	Puget Western, Inc., a wholly owned subsidiary of PSE, Promissory Note.
	PSE's senior secured notes will cease to be secured by the pledged first mortgage bonds on the date that all of the first mortgage bonds issued and outstanding under the electric or natural gas utility mortgage indenture have been retired.  As of December 31, 2014, the latest maturity date of the first mortgage bonds, other than pledged first mortgage bonds, is December 22, 2025.
	Puget Sound Energy Long-Term Debt
	PSE has in effect a shelf registration statement under which it may issue, from time to time, up to $800 million aggregate principal amount of senior notes secured by pledged first mortgage bonds.  The Company remains subject to the restrictions of PSE’s indentures and credit agreements on the amount of first mortgage bonds that PSE may issue.
	Substantially all utility properties owned by PSE are subject to the lien of the Company’s electric and natural gas mortgage indentures.  To issue additional first mortgage bonds under these indentures, PSE’s earnings available for interest must exceed certain minimums as defined in the indentures.  At December 31, 2014, the earnings available for interest exceeded the required amount.
	Puget Sound Energy Pollution Control Bonds
	PSE has two series of Pollution Control Bonds (the Bonds) outstanding.  Amounts outstanding were borrowed from the City of Forsyth, Montana who obtained the funds from the sale of Customized Pollution Control Refunding Bonds issued to finance pollution control facilities at Colstrip Units 3 & 4.
	In May 2013, PSE refinanced $161.9 million of the Bonds to a lower weighted average interest rate from 5.01% to 3.91%. The Bonds will mature on March 1, 2031. On or after March 1, 2023, the Company may elect to call the bonds at a redemption price of 100% of the principal amount thereof, without premium, plus accrued interest, if any, to the redemption date. Due to the refinance of the Bonds, Puget Energy wrote off $18.0 million of fair value related to the Bonds that were redeemed to interest expense.
	Each series of the Bonds is collateralized by a pledge of PSE’s first mortgage bonds, the terms of which match those of the Bonds.  No payment is due with respect to the related series of first mortgage bonds so long as payment is made on the Bonds.
	Puget Energy Long-Term Debt
	At the time of the merger in 2009, Puget Energy entered into a $1.225 billion five-year term-loan and a $1.0 billion five-year capital expenditure credit facility for funding capital expenditures. In February 2012, Puget Energy entered into a $1.0 billion five-year revolving senior secured credit facility and the 2009 term loan and capital expenditure facilities were terminated. Concurrent with the closing of the new PSE credit facilities in February 2013, the Company reduced the size of Puget Energy's credit facility to $800.0 million. The Puget Energy revolving senior secured credit facility also has an accordion feature that, upon the banks' approval, would increase the size of the facility to $1.3 billion. In April 2014, the Company completed an amendment to the senior secured credit facility, extending the maturity from February 2017 to April 2018, updating the fee structure, eliminating a financial covenant and updating or clarifying the definitions of other terms and conditions of the facility. All other terms and conditions of that facility remain unchanged from when it was committed in 2012. As a revolving facility, amounts borrowed may be repaid without a reduction in the size of the facility.
	The Puget Energy revolving senior secured credit facility contains usual and customary affirmative and negative covenants.  The agreement also contains a financial covenant based on the Maximum Leverage Ratio, as defined in the agreement governing the senior secured credit facility.
	In June 2014, Puget Energy entered into three bilateral term loans, with two and three year maturities, which in total, equal $299 million. The proceeds of the term loans were used to pay off the outstanding Puget Energy revolving credit facility balance, which subsequently allows the Company to carry the debt with lower interest expense. All other terms, conditions and covenants are consistent with each other and the credit facility agreement, with the exception of maturity and price.
	Long-Term Debt Maturities
	The principal amounts of long-term debt maturities for the next five years and thereafter are as follows:
	(Dollars in Thousands)	2015			2016			2017		2018		2019		Thereafter		Total
	Maturities of:
	PSE long-term debt	$	162,000		$	250,000		$	2,412	$	200,000	$	—	$	3,148,860	$	3,763,272
	Puget Energy long-term debt	—			199,000			100,000		—		—		1,400,000		1,699,000
	Puget Energy long-term debt	$	162,000		$	449,000		$	102,412	$	200,000	$	—	$	4,548,860	$	5,462,272
	Financial Covenants
	Puget Energy's credit facility contains a financial covenant related to maximum leverage. As of December 31, 2014, the Company is in compliance with its long-term debt financial covenants.

Liquidity_Facilities_and_Other

Liquidity Facilities and Other Financing Arrangements	12 Months Ended
	Dec. 31, 2014
Liquidity Facilities and Other Financing Arrangements [Abstract]
Liquidity Facilities and Other Financing Arrangements	Liquidity Facilities and Other Financing Arrangements
	As of December 31, 2014 and 2013, PSE had $85.0 million and $162.0 million in short-term debt outstanding, respectively, exclusive of the demand promissory note with Puget Energy.  Outside of the consolidation of PSE’s short-term debt, Puget Energy had no short-term debt outstanding in either year as borrowings under its credit facilities are classified as long-term.  PSE’s weighted-average interest rate on short-term debt, including borrowing rate, commitment fees and the amortization of debt issuance costs, during 2014 and 2013 was 4.05% and 3.93%, respectively.  As of December 31, 2014, PSE and Puget Energy had several committed credit facilities that are described below.
	Puget Sound Energy Credit Facilities
	PSE has two unsecured revolving credit facilities which provide, in aggregate, $1.0 billion of short-term liquidity needs. These facilities consist of a $650.0 million revolving liquidity facility (which includes a liquidity letter of credit facility and a swingline facility) to be used for general corporate purposes, including a backstop to the Company's commercial paper program and a $350.0 million revolving energy hedging facility (which includes an energy hedging letter of credit facility). The $650.0 million liquidity facility includes a swingline feature allowing same day availability on borrowings up to $75.0 million. The credit facilities also have an accordion feature which, upon the banks' approval, would increase the total size of these facilities to $1.450 billion.
	In April 2014, the Company completed a one-year extension on both of the liquidity and hedging facilities, extending the maturity from February 2018 to April 2019, and updating or clarifying the definitions of other terms and conditions of the facilities from when they were committed in 2013. The credit agreements are syndicated among numerous lenders and contain usual and customary affirmative and negative covenants that, among other things, place limitations on PSE's ability to transact with affiliates, make asset dispositions and investments or permit liens to exist. The credit agreements also contain a financial covenant of total debt to total capitalization of 65% or less. PSE certifies its compliance with such covenants to participating banks each quarter. As of December 31, 2014, PSE was in compliance with all applicable covenant ratios.
	The credit agreements provide PSE with the ability to borrow at different interest rate options. The credit agreements allow PSE to borrow at the bank's prime rate or to make floating rate advances at the London Interbank Offered Rate (LIBOR) plus a spread that is based upon PSE's credit rating. PSE must pay a commitment fee on the unused portion of the credit facilities. The spreads and the commitment fee depend on PSE's credit ratings. As of the date of this report, the spread to the LIBOR is 1.25% and the commitment fee is 0.175%.
	As of December 31, 2014, no amounts were drawn and outstanding under PSE's liquidity facility. No amounts were drawn and outstanding under the $350.0 million energy hedging facility. No letters of credit were outstanding under either facility, and $85.0 million was outstanding under the commercial paper program. Outside of the credit agreements, PSE had a $4.2 million letter of credit in support of a long-term transmission contract and a $1.0 million letter of credit in support of natural gas purchases in Canada.
	Demand Promissory Note
	In 2006, PSE entered into a revolving credit facility with Puget Energy, in the form of a credit agreement and a Demand Promissory Note (Note) pursuant to which PSE may borrow up to $30.0 million from Puget Energy subject to approval by Puget Energy.  Under the terms of the Note, PSE pays interest on the outstanding borrowings based on the lower of the weighted-average interest rates of PSE’s outstanding commercial paper interest rate or PSE’s senior unsecured revolving credit facility.  Absent such borrowings, interest is charged at one-month LIBOR plus 0.25%.  At December 31, 2014, the outstanding balance of the Note was $28.9 million.  The outstanding balance and the related interest under the Note are eliminated by Puget Energy upon consolidation of PSE’s financial statements.
	Puget Energy Credit Facility
	At December 31, 2014, Puget Energy maintained an $800.0 million revolving senior secured credit facility. In April, 2014, the Company completed an amendment to the senior secured credit facility, extending the maturity from February 2017 to April 2018, updating the fee structure, eliminating a financial covenant and updating or clarifying the definitions of other terms and conditions of the facility. The Puget Energy revolving senior secured credit facility also has an accordion feature which, upon the banks' approval, would increase the size of the facility to $1.3 billion.
	The revolving senior secured credit facility provides Puget Energy the ability to borrow at different interest rate options and includes variable fee levels. Interest rates may be based on the bank's prime rate or LIBOR plus a spread based on Puget Energy's credit ratings. Puget Energy must pay a commitment fee on the unused portion of the facility. As of December 31, 2014, there was no amount drawn and outstanding under the facility. As a result of Puget Energy's credit rating upgrade in 2014, the spread over LIBOR was 1.75% and the commitment fee was 0.28% as of the date of this report. Puget Energy entered into interest rate swap contracts to manage the interest rate risk associated with the credit facility or similar variable rate debt.
	The revolving senior secured credit facility contains usual and customary affirmative and negative covenants. The agreement also contains a Maximum Leverage Ratio financial covenant as defined in the agreement governing the senior secured credit facility. As of December 31, 2014, Puget Energy was in compliance with all applicable covenants.

Leases

Leases	12 Months Ended
	Dec. 31, 2014
Leases [Abstract]
Leases	Leases
	PSE leases buildings and assets under operating leases.    Certain leases contain purchase options, renewal options and escalation provisions.  Operating lease expenses net of sublease receipts were:
	(Dollars in Thousands)
	At December 31,
	2014	$	30,737
	2013	29,392
	2012	29,661
	Payments received for the subleases of properties were immaterial for each of the years ended 2014, 2013 and 2012.
	Future minimum lease payments for non-cancelable leases net of sublease receipts are:
	(Dollars in Thousands)
	At December 31,	Operating		Capital
	2015	$	17,677	$	8,160
	2016	21,454		2,178
	2017	22,179		—
	2018	20,423		—
	2019	15,180		—
	Thereafter	120,791		—
	Total minimum lease payments	$	217,704	$	10,338

Accounting_for_Derivative_Inst

Accounting for Derivative Instruments and Hedging Activities	12 Months Ended
	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Accounting for Derivative Instruments and Hedging Activities	Accounting for Derivative Instruments and Hedging Activities
	PSE employs various energy portfolio optimization strategies, but is not in the business of assuming risk for the purpose of realizing speculative trading revenue. The nature of serving regulated electric customers with its portfolio of owned and contracted electric generation resources exposes PSE and its customers to some volumetric and commodity price risks within the sharing mechanism of the PCA. Therefore, wholesale market transactions and PSE's related hedging strategies are focused on reducing costs and risks where feasible, thus reducing volatility in costs in the portfolio. In order to manage its exposure to the variability in future cash flows for forecasted energy transactions, PSE utilizes a programmatic hedging strategy which extends out three years. PSE's energy risk portfolio management function monitors and manages these risks using analytical models and tools. In order to manage risks effectively, PSE enters into forward physical electric and natural gas purchase and sale agreements, fixed-for-floating swap contracts, and commodity call/put options. The forward physical electric agreements are both fixed and variable (at index), while the physical natural gas contracts are variable. To fix the price of wholesale electricity and natural gas, PSE may enter into fixed-for-floating swap (financial) contracts with various counterparties. PSE also utilizes natural gas call and put options as an additional hedging instrument to increase the hedging portfolio's flexibility to react to commodity price fluctuations.
	The Company manages its interest rate risk through the issuance of mostly fixed-rate debt with varied maturities. The Company utilizes internal cash from operations, borrowings under its commercial paper program, and its credit facilities to meet short-term funding needs. The Company may enter into swap instruments or other financial hedge instruments to manage the interest rate risk associated with these debts. As of December 31, 2014, Puget Energy had two interest rate swap contracts outstanding which extend to January 2017. PSE did not have any outstanding interest rate swap instruments.
	The following table presents the volumes, fair values and locations of the Company's derivative instruments recorded on the balance sheets:
	Puget Energy and	Year Ended December 31,
	Puget Sound Energy
	(Dollars in Thousands)	Volumes (millions)				Assets 1						Liabilities 2
		2014		2013		2014			2013			2014			2013
	Interest rate swap derivatives 3	$450.00		$450.00		$	—		$	—		$	9,073		$	13,223
	Electric portfolio derivatives	*		*		4,822			18,479			107,228			37,312
	Natural gas derivatives (MMBtus) 4	360.4		423.5		19,526			8,121			88,807			35,676
	Total derivative contracts					$	24,348		$	26,600		$	205,108		$	86,211
	Current					$	21,178		$	18,867		$	142,195		$	48,049
	Long-term					3,170			7,733			62,913			38,162
	Total derivative contracts					$	24,348		$	26,600		$	205,108		$	86,211
	___________
	1	Balance sheet location: Current and Long-term Unrealized gain on derivative instruments.
	2	Balance sheet location: Current and Long-term Unrealized loss on derivative instruments.
	3	Interest rate swap contracts are only held at Puget Energy.
	4	PSE had a net derivative liability and an offsetting regulatory asset of $69.3 million at December 31, 2014 and $27.6 million at December 31, 2013 related to contracts used to economically hedge the cost of physical gas purchased to serve natural gas customers. All fair value adjustments on derivatives relating to the natural gas business have been deferred in accordance with ASC 980, due to the PGA mechanism.
	*	Electric portfolio derivatives consist of electric generation fuel of 140.2 million One Million British Thermal Units (MMBtus) and purchased electricity of 5.4 million Megawatt Hours (MWhs) at December 31, 2014 and 145.6 million MMBtus and 8.6 million MWhs at December 31, 2013.
	For further details regarding the fair value of derivative instruments, see Note 10.
	It is the Company's policy to record all derivative transactions on a gross basis at the contract level, without offsetting assets or liabilities. The Company generally enters into transactions using the following master agreements: WSPP, Inc. (WSPP) agreements which standardize physical power contracts; ISDA agreements which standardize financial gas and electric contracts; and NAESB agreements which standardize physical gas contracts. The Company believes that such agreements reduce credit risk exposure because such agreements provide for the netting and offsetting of monthly payments as well as right of set-off in the event of counterparty default. The set-off provision can be used as a final settlement of accounts which extinguishes the mutual debts owed between the parties in exchange for a new net amount.
	The following tables present the potential effect of netting arrangements, including rights of set-off associated with the Company's derivative assets and liabilities:
	Puget Energy and Puget Sound Energy
	At December 31, 2014
	(Dollars in Thousands)	Gross Amounts Recognized in the Statement of Financial Position 1			Gross Amounts Offset in the Statement of Financial Position			Net of Amounts Presented in the Statement of Financial Position			Gross Amounts Not Offset in the Statement of Financial Position
											Commodity Contracts			Cash Collateral Received/Posted			Net Amount
	Assets
	Energy Derivative Contracts	$	24,348		$	—		$	24,348		$	(23,066	)	$	—		$	1,282
	Liabilities
	Energy Derivative Contracts	$	196,035		$	—		$	196,035		$	(23,066	)	$	(20	)	$	172,949
	Interest Rate Swaps 2	$	9,073		$	—		$	9,073		$	—		$	—		$	9,073
	Puget Energy and Puget Sound Energy
	At December 31, 2013
	(Dollars in Thousands)	Gross Amounts Recognized in the Statement of Financial Position 1			Gross Amounts Offset in the Statement of Financial Position			Net of Amounts Presented in the Statement of Financial Position			Gross Amounts Not Offset in the Statement of Financial Position
											Commodity Contracts			Cash Collateral Received/Posted			Net Amount
	Assets
	Energy Derivative Contracts	$	26,600		$	—		$	26,600		$	(19,491	)	$	—		$	7,109
	Liabilities
	Energy Derivative Contracts	$	72,988		$	—		$	72,988		$	(19,491	)	$	—		$	53,497
	Interest Rate Swaps 2	$	13,223		$	—		$	13,223		$	—		$	—		$	13,223
	___________
	1.	All Derivative Contract deals are executed under ISDA, NAESB and WSPP Master Netting Agreements with Right of Offset.
	2	Interest Rate Swap Contracts are only held at Puget Energy.
	Due to the merger in 2009, Puget Energy recorded all derivative contracts at fair value as either assets or liabilities. Certain contracts meeting the criteria defined in ASC 815 were subsequently designated as NPNS or cash flow hedges, thereby causing differences in the derivative unrealized gains/losses to be recorded through earnings between Puget Energy and PSE. These differences will occur through February 2015.
	The following tables present the effect and locations of the Company's derivatives not designated as hedging instruments, recorded on the statements of income:
	Puget Energy		Year Ended December 31,
	(Dollars in Thousands)	Location	2014			2013			2012
	Interest rate contracts:	Other deductions	$	(3,915	)	$	2,420		$	(4,288	)
		Interest expense	500			(5,904		)	(29,727		)
	Commodity contracts:
	Electric derivatives	Unrealized gain (loss) on derivative instruments, net 1	(84,146		)	102,744			131,407
		Electric generation fuel	6,511			(27,008		)	(66,762		)
		Purchased electricity	(4,212		)	(38,299		)	(138,551		)
	Total gain (loss) recognized in income on derivatives		$	(85,262	)	$	33,953		$	(107,921	)
	___________
	1	For 2012, the amount differs from the amount stated in the statement of income as it does not include amortization related to contracts that were recorded at fair value at the time of the February 2009 merger and subsequently designated as NPNS of $2.2 million for the year ended December 31, 2012.
	Puget Sound Energy		Year Ended December 31,
	(Dollars in Thousands)	Location	2014			2013			2012
	Commodity contracts:
	Electric derivatives	Unrealized gain (loss) on derivative instruments, net	$	(85,636	)	$	98,880		$	119,120
		Electric generation fuel	6,511			(27,008		)	(66,762		)
		Purchased electricity	(4,212		)	(38,299		)	(138,551		)
Total gain (loss) recognized in income on derivatives		$	(83,337	)	$	33,573		$	(86,193	)
The unrealized gain or loss on derivative contracts is reported in the statement of cash flows under the operating activities section. However, at the time of the merger in 2009, all derivative contracts at Puget Energy were assessed to identify contracts that have a “more than an insignificant” fair value. If the fair value was greater than 10% of the notional value, the contract was deemed as having a financing element. For those contracts, the cash inflows (outflows) are presented in the financing activities section of the statement of cash flows. For the years ended December 31, 2014, 2013 and 2012, cash outflows related to financing activities of $16.3 million, $34.3 million and $92.7 million, respectively, were reported on Puget Energy's statement of cash flows.
For derivative instruments previously designated as cash flow hedges (including both commodity and interest rate swap contracts), the effective portion of the gain or loss on the derivative was recorded as a component of OCI, and then is reclassified into earnings in the same period(s) during which the hedged transaction affects earnings.
Puget Energy and PSE expect $0.5 million and $1.1 million of losses, respectively, in accumulated OCI will be reclassified into earnings within the next twelve months. The Company does not attempt cash flow hedging for any new transactions and records all mark-to-market adjustments through earnings.
The following tables present the Company's pre-tax gain (loss) on derivatives that were previously in a cash flow hedge relationship, and subsequently reclassified out of accumulated OCI into income:
Puget Energy		Year Ended December 31,
(Dollars in Thousands)	Location	2014			2013			2012
Interest rate contracts:	Interest expense	$	(144	)	$	(4,505	)	$	(17,811	)
Commodity contracts:
Electric derivatives	Electric generation fuel	—			—			100
	Purchased electricity	(572		)	(57		)	(671		)
Total		$	(716	)	$	(4,562	)	$	(18,382	)
Puget Sound Energy		Year Ended December 31,
(Dollars in Thousands)	Location	2014			2013			2012
Interest rate contracts:	Interest expense	$	(488	)	$	(488	)	$	(488	)
Commodity contracts:
Electric derivatives	Electric generation fuel	—			—			97
	Purchased electricity	(2,063		)	(3,922		)	(12,955		)
Total		$	(2,551	)	$	(4,410	)	$	(13,346	)
The Company is exposed to credit risk primarily through buying and selling electricity and natural gas to serve its customers. Credit risk is the potential loss resulting from a counterparty's non-performance under an agreement. The Company manages credit risk with policies and procedures for, among other things, counterparty credit analysis, exposure measurement, exposure monitoring and exposure mitigation.
The Company monitors counterparties that have significant swings in credit default swap rates, have credit rating changes by external rating agencies, have changes in ownership or are experiencing financial distress. Where deemed appropriate, the Company may request collateral or other security from its counterparties to mitigate potential credit default losses. Criteria employed in this decision include, among other things, the perceived creditworthiness of the counterparty and the expected credit exposure.
It is possible that volatility in energy commodity prices could cause the Company to have material credit risk exposure with one or more counterparties. If such counterparties fail to perform their obligations under one or more agreements, the Company could suffer a material financial loss. However, as of December 31, 2014, approximately 99.3% of the Company's energy portfolio exposure, excluding NPNS transactions, is with counterparties that are rated at least investment grade by the major rating agencies and 0.7% are either rated below investment grade or not rated by rating agencies. The Company assesses credit risk internally for counterparties that are not rated.
As the Company generally enters into transactions using the WSPP, ISDA and NAESB master agreements, it believes that such agreements reduce credit risk exposure because they provide for the netting and offsetting of monthly payments and, in the event of counterparty default, termination payments.
The Company computes credit reserves at a master agreement level by counterparty (i.e., WSPP, ISDA, or NAESB). The Company considers external credit ratings and market factors, such as credit default swaps and bond spreads, in the determination of reserves. The Company recognizes that external ratings may not always reflect how a market participant perceives a counterparty's risk of default. The Company uses both default factors published by Standard & Poor's and factors derived through analysis of market risk, which reflect the application of an industry standard recovery rate. The Company selects a default factor by counterparty at an aggregate master agreement level based on a weighted-average default tenor for that counterparty's deals. The default tenor is determined by weighting the fair value and contract tenors for all deals for each counterparty to derive an average value. The default factor used is dependent upon whether the counterparty is in a net asset or a net liability position after applying the master agreement levels.
The Company applies the counterparty's default factor to compute credit reserves for counterparties that are in a net asset position. The Company calculates a non-performance risk on its derivative liabilities by using its estimated incremental borrowing rate over the risk-free rate. Credit reserves are netted against unrealized gain (loss) positions. As of December 31, 2014, the Company was in a net liability position with the majority of counterparties, so the default factors of counterparties did not have a significant impact on reserves for the quarter. The majority of the Company's derivative contracts are with financial institutions and other utilities operating within the Western Electricity Coordinating Council. As of December 31, 2014, PSE has posted a $1.0 million letter of credit as a condition of transacting on a physical energy exchange and clearinghouse in Canada. PSE did not trigger any collateral requirements with any of its counterparties nor were any of PSE's counterparties required to post collateral resulting from credit rating downgrades.
The table below presents the fair value of the overall contractual contingent liability positions for the Company's derivative activity at December 31, 2014:
Puget Energy and Puget Sound Energy	Fair Value 1			Posted			Contingent
Contingent Feature	Liability			Collateral			Collateral
(Dollars in Thousands)
Credit rating 2	$	(37,398	)	$	—		$	37,398
Requested credit for adequate assurance	(66,468		)	—			—
Forward value of contract 3	(2,490		)	—			—
Total	$	(106,356	)	$	—		$	37,398
__________
1	Represents the derivative fair value of contracts with contingent features for counterparties in net derivative liability positions. Excludes NPNS, accounts payable and accounts receivable.
2	Failure by PSE to maintain an investment grade credit rating from each of the major credit rating agencies provides counterparties a contractual right to demand collateral.
3	Collateral requirements may vary, based on changes in the forward value of underlying transactions relative to contractually defined collateral thresholds.

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements
	ASC 820 established a fair value hierarchy that prioritizes the inputs used to measure fair value. The hierarchy categorizes the inputs into three levels with the highest priority given to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurement) and the lowest priority given to unobservable inputs (Level 3 measurement). The three levels of the fair value hierarchy are as follows:
	Level 1 - Quoted prices are available in active markets for identical assets or liabilities as of the reporting date. Level 1 primarily consists of financial instruments such as exchange-traded derivatives and listed equities. Equity securities that are also classified as cash equivalents are considered Level 1 if there are unadjusted quoted prices in active markets for identical assets or liabilities.
	Level 2 - Pricing inputs are other than quoted prices in active markets included in Level 1, which are either directly or indirectly observable as of the reporting date. Level 2 includes those financial instruments that are valued using models or other valuation methodologies. Instruments in this category include non-exchange-traded derivatives such as over-the-counter forwards and options.
	Level 3 - Pricing inputs include significant inputs that have little or no observability as of the reporting date. These inputs may be used with internally developed methodologies that result in management's best estimate of fair value.
	Financial assets and liabilities measured at fair value are classified in their entirety in the appropriate fair value hierarchy based on the lowest level of input that is significant to the fair value measurement. The Company's assessment of the significance of a particular input to the fair value measurement requires judgment, and may affect the valuation of fair value assets and liabilities and their placement within the fair value hierarchy. The Company primarily determines fair value measurements classified as Level 2 or Level 3 using a combination of the income and market valuation approaches. The process of determining the fair values is the responsibility of the derivative accounting department which reports to the Controller and Principal Accounting Officer. Inputs used to estimate the fair value of forwards, swaps and options include market-price curves; contract terms and prices; credit-risk adjustments; and discount factors. Additionally, for options, the Black-Scholes option valuation model and implied market volatility curves are used. Inputs used to estimate fair value in industry-standard models are categorized as Level 2 inputs because substantially all assumptions and inputs are observable in active markets throughout the full term of the instruments. On a daily basis, the Company obtains quoted forward prices for the electric and natural gas markets from an independent external pricing service. For interest rate swaps, the Company obtains monthly mark-to-market values from an independent external pricing service for LIBOR forward rates, which is a significant input. Some of the inputs of the interest rate swap valuations, which are less significant, include the credit standing of the counterparties, assumptions for time value and the impact of the Company's nonperformance risk of its liabilities. The Company classifies cash and cash equivalents, and restricted cash as Level 1 financial instruments due to cash being at stated value, and cash equivalents at quoted market prices.
	The Company considers its electric, natural gas and interest rate swap contracts as Level 2 derivative instruments as such contracts are commonly traded as over-the-counter forwards with indirectly observable price quotes. Management's assessment was based on the trading activity in real-time and forward electric and natural gas markets. Each quarter, the Company confirms the validity of pricing-service quoted prices (e.g., Level 2 in the fair value hierarchy) used to value commodity contracts with the actual prices of commodity contracts entered into during the most recent quarter. However, certain energy derivative instruments with maturity dates falling outside the range of observable price quotes are classified as Level 3 in the fair value hierarchy.
	Assets and Liabilities with Estimated Fair Value
	The following table presents the carrying value for cash, cash equivalents, restricted cash, notes receivable and short-term debt by level, within the fair value hierarchy. The carrying values below are representative of fair values due to the short-term nature of these financial instruments.
	Puget Energy	Carrying / Fair Value									Carrying / Fair Value
		At December 31, 2014									At December 31, 2013
	(Dollars in Thousands)	Level 1			Level 2			Total			Level 1			Level 2			Total
	Assets:
	Cash and Cash Equivalents	$	37,527		$	—		$	37,527		$	44,302		$	—		$	44,302
	Restricted Cash	32,863			—			32,863			7,171			—			7,171
	Notes Receivable and Other	—			53,503			53,503			—			53,449			53,449
	Total assets	$	70,390		$	53,503		$	123,893		$	51,473		$	53,449		$	104,922
	Liabilities:
	Short-term debt	$	85,000		$	—		$	85,000		$	162,000		$	—		$	162,000
	Total liabilities	$	85,000		$	—		$	85,000		$	162,000		$	—		$	162,000
	Puget Sound Energy	Carrying / Fair Value									Carrying / Fair Value
		At December 31, 2014									At December 31, 2013
	(Dollars in Thousands)	Level 1			Level 2			Total			Level 1			Level 2			Total
	Assets:
	Cash and Cash Equivalents	$	37,466		$	—		$	37,466		$	44,111		$	—		$	44,111
	Restricted Cash	32,863			—			32,863			7,171			—			7,171
	Notes Receivable and Other	—			53,503			53,503			—			53,449			53,449
	Total assets	$	70,329		$	53,503		$	123,832		$	51,282		$	53,449		$	104,731
	Liabilities:
	Short-term debt	$	85,000		$	—		$	85,000		$	162,000		$	—		$	162,000
	Short-term debt owed to parent	—			28,933			28,933			—			29,598			29,598
	Total liabilities	$	85,000		$	28,933		$	113,933		$	162,000		$	29,598		$	191,598
	The fair value of the junior subordinated and long-term notes were estimated using the discounted cash flow method with U.S. Treasury yields and Company credit spreads as inputs, interpolating to the maturity date of each issue. Carrying values and estimated fair values were as follows:
	Puget Energy		December 31, 2014						December 31, 2013
	(Dollars in Thousands)	Level	Carrying			Fair			Carrying			Fair
			Value			Value			Value			Value
	Liabilities:
	Junior subordinated notes	2	$	250,000		$	276,235		$	250,000		$	269,366
	Long-term debt (fixed-rate), net of discount	2	4,694,608			6,083,554			4,683,476			5,594,314
	Long-term debt (variable-rate)	2	299,000			299,000			299,000			299,000
	Total		$	5,243,608		$	6,658,789		$	5,232,476		$	6,162,680
	Puget Sound Energy		December 31, 2014						December 31, 2013
	(Dollars in Thousands)	Level	Carrying			Fair			Carrying			Fair
			Value			Value			Value			Value
	Liabilities:
	Junior subordinated notes	2	$	250,000		$	276,235		$	250,000		$	269,366
	Long-term debt (fixed-rate), net of discount	2	3,513,259			4,437,473			3,513,258			4,038,455
	Total		$	3,763,259		$	4,713,708		$	3,763,258		$	4,307,821
	Assets and Liabilities Measured at Fair Value on a Recurring Basis
	The following tables present the Company's financial assets and liabilities by level, within the fair value hierarchy, that were accounted for at fair value on a recurring basis and the reconciliation of the changes in the fair value of Level 3 derivatives in the fair value hierarchy:
	Puget Energy	Fair Value									Fair Value
		At December 31, 2014									At December 31, 2013
	(Dollars in Thousands)	Level 2			Level 3			Total			Level 2			Level 3			Total
	Interest rate derivative instruments	$	9,073		$	—		$	9,073		$	13,223		$	—		$	13,223
	Total derivative liabilities	$	9,073		$	—		$	9,073		$	13,223		$	—		$	13,223
	Puget Energy and	Fair Value									Fair Value
	Puget Sound Energy	At December 31, 2014									At December 31, 2013
	(Dollars in Thousands)	Level 2			Level 3			Total			Level 2			Level 3			Total
	Assets:
	Electric derivative instruments	$	1,654		$	3,168		$	4,822		$	14,661		$	3,818		$	18,479
	Natural gas derivative instruments	18,064			1,462			19,526			5,448			2,673			8,121
	Total assets	$	19,718		$	4,630		$	24,348		$	20,109		$	6,491		$	26,600
	Liabilities:
	Electric derivative instruments	$	91,998		$	15,230		$	107,228		$	18,073		$	19,239		$	37,312
Natural gas derivative instruments	85,305			3,502			88,807			32,642			3,034			35,676
Total liabilities	$	177,303		$	18,732		$	196,035		$	50,715		$	22,273		$	72,988
Puget Energy and	Year Ended December 31,
Puget Sound Energy
Level 3 Roll-Forward Net (Liability)	2014									2013									2012
(Dollars in Thousands)	Electric			Gas			Total			Electric			Gas			Total			Electric			Gas			Total
Balance at beginning of period	$	(15,421	)	$	(361	)	$	(15,782	)	$	(33,924	)	$	(1,602	)	$	(35,526	)	$	(90,311	)	$	(5,041	)	$	(95,352	)
Changes during period
Realized and unrealized energy derivatives:
Included in earnings 1	(5,537		)	—			(5,537		)	(10,491		)	—			(10,491		)	(21,362		)	—			(21,362		)
Included in regulatory assets / liabilities	—			1,630			1,630			—			(945		)	(945		)	—			(1,937		)	(1,937		)
Settlements 2	1,036			(1,534		)	(498		)	11,609			(754		)	10,855			59,133			969			60,102
Transferred into Level 3	5,155			(585		)	4,570			(7,799		)	—			(7,799		)	(55,548		)	(297		)	(55,845		)
Transferred out of Level 3	2,705			(1,190		)	1,515			25,184			2,940			28,124			74,164			4,704			78,868
Balance at end of period	$	(12,062	)	$	(2,040	)	$	(14,102	)	$	(15,421	)	$	(361	)	$	(15,782	)	$	(33,924	)	$	(1,602	)	$	(35,526	)
_______________
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 $(9.6) million, $(13.4) million, and $(15.2) million for the years ended December 31, 2014, 2013 and 2012, respectively.
2	The Company had no purchases, sales or issuances during the reported periods.
Realized gains and losses on energy derivatives for Level 3 recurring items are included in energy costs in the Company's consolidated statements of income under purchased electricity, electric generation fuel or purchased natural gas when settled. Unrealized gains and losses on energy derivatives for Level 3 recurring items are included in net unrealized (gain) loss on derivative instruments in the Company's consolidated statements of income.
In order to determine which assets and liabilities are classified as Level 3, the Company receives market data from its independent external pricing service defining the tenor of observable market quotes. To the extent any of the Company's commodity contracts extend beyond what is considered observable as defined by its independent pricing service, the contracts are classified as Level 3. The actual tenor of what the independent pricing service defines as observable is subject to change depending on market conditions. Therefore, as the market changes, the same contract may be designated Level 3 one month and Level 2 the next, and vice versa. The changes of fair value classification into or out of Level 3 are recognized each month, and reported in the Level 3 Roll-forward table above. The Company did not have any transfers between Level 2 and Level 1 during the years ended December 31, 2014 and 2013. The Company does periodically transact at locations, or market price points, that are illiquid or for which no prices are available from the independent pricing service. In such circumstances the Company uses a more liquid price point and performs a 15-month regression against the illiquid locations to serve as a proxy for market prices. Such transactions are classified as Level 3. The Company does not use internally developed models to make adjustments to significant unobservable pricing inputs.
The only significant unobservable input into the fair value measurement of the Company's Level 3 assets and liabilities is the forward price for electric and natural gas contracts. Below are the forward price ranges for the Company's commodity contracts, as of December 31, 2014:
(Dollars in Thousands)
	Fair Value				Range
Derivative Instrument	Assets 1	Liabilities 1	Valuation Technique	Unobservable Input	Low	High	Weighted Average
Electric	$3,168	$15,230	Discounted cash flow	Power Prices	$21.79 per MWh	$35.46 per MWh	$32.89 per MWh
Natural gas	$1,462	$3,502	Discounted cash flow	Natural Gas Prices	$3.11 per MMBtu	$3.83 per MMBtu	$3.28 per MMBtu
_______________
1	The valuation techniques, unobservable inputs and ranges are the same for asset and liability positions.
The significant unobservable inputs listed above would have a direct impact on the fair values of the above instruments if they were adjusted. Consequently significant increases or decreases in the forward prices of electricity or natural gas in isolation would result in a significantly higher or lower fair value for Level 3 assets and liabilities. Generally, interrelationships exist between market prices of natural gas and power. As such, an increase in natural gas pricing would potentially have a similar impact on forward power markets. At December 31, 2014, a hypothetical 10% increase or decrease in market prices of natural gas and electricity would change the fair value of the Company's derivative portfolio, classified as Level 3 within the fair value hierarchy, by $3.9 million.
Long-Lived Assets Measured at Fair Value on a Nonrecurring Basis
At the time of merger, Puget Energy recorded the fair value of its intangible assets in accordance with ASC 360, “Property, Plant, and Equipment,” (ASC 360). The fair value assigned to the power contracts was determined using an income approach comparing the contract rate to the market rate for power over the remaining period of the contracts incorporating non-performance risk. Management also incorporated certain assumptions related to quantities and market presentation that it believes market participants would make in the valuation. The fair value of the power contracts is amortized as the contracts settle.
ASC 360 requires long-lived assets to be tested for impairment on an annual basis, and upon the occurrence of any events or circumstances that would be more likely than not to reduce the fair value of the long-lived assets below their carrying value. One such triggering event is a significant decrease in the forward market prices of power.
At December 31, 2014, Puget Energy completed a valuation and impairment test of its purchased power contracts classified as intangible assets. The valuation indicated a fair value of $437.6 million with an impairment to the Wells hydro contract. As of December 31, 2014, the carrying value for this contract was $65.3 million and its fair value on a discounted basis was $62.1 million, thereby requiring a write-down of $3.2 million to this intangible asset with a corresponding reduction in the regulatory liability.
Below are significant unobservable inputs used in estimating the impaired long term power purchase contract's fair value on December 31, 2014:
Valuation Technique	Unobservable Input	Low	High	Average
Discounted cash flow	Power prices	$19.30 per MWh	$37.06 per MWh	$29.53 per MWh
Discounted cash flow	Power contract costs (in thousands)	$3,015 per qtr	$4,783 per qtr	$4,469 per qtr
At June 30, 2013, Puget Energy completed a valuation and impairment test of its purchased power contracts classified as intangible assets. The valuation indicated a fair value of $484.1 million with an impairment to the Priest Rapids Reasonable Portion intangible asset contract. As of June 30, 2013, the carrying value for this intangible asset contract was $47.1 million and its fair value on a discounted basis was determined to be an asset of $33.6 million, thereby requiring a write-down of $13.5 million to the intangible asset with a corresponding reduction in the regulatory liability.
Below are significant unobservable inputs used in estimating the impaired long term power purchase contract's fair value on June 30, 2013:
Valuation Technique	Unobservable Input	Low	High	Average
Discounted cash flow	Power prices	$30.85 per MWh	$65.35 per MWh	$48.47 per MWh
Discounted cash flow	Power contract costs (in thousands)	$389 per yr	$6,845 per yr	$4,110 per yr
The valuations were measured using the income approach. Significant inputs included forward electricity prices and power contract pricing which provided future net cash flow estimates which are classified as Level 3 within the fair value hierarchy. A less significant input is the discount rate reflective of PSE's cost of capital used in the valuation.

Employee_Investment_Plans

Employee Investment Plans	12 Months Ended
	Dec. 31, 2014
Employee Investment Plans [Abstract]
Employee Investment Plans	Employee Investment Plans
	The Company's Investment Plan is a qualified employee 401(k) plan, under which employee salary deferrals and after-tax contributions are used to purchase several different investment fund options.  PSE’s contributions to the employee Investment Plan were $14.9 million, $14.6 million and $14.5 million for the years 2014, 2013, and 2012, respectively.  The employee Investment Plan eligibility requirements are set forth in the plan documents.
	Non-represented employees and United Association of Journeymen and Apprentices of the Plumbing and Pipefitting Industry (UA) represented employees hired before January 1, 2014, and International Brotherhood of Electrical Workers Local Union 77 (IBEW) represented employees hired before December 12, 2014, have the following company contributions:
	•	For employees under the Cash Balance retirement plan formula, PSE will match 100% of an employee's contribution up to 6% of plan compensation each paycheck, and will make an additional year-end contribution equal to 1% of base pay.
	•	For employees grandfathered under the Final Average Earning retirement plan formula, PSE will match 55% of an employee’s contribution up to 6% of plan compensation each paycheck.
	UA-represented employees hired on or after January 1, 2014 will have access to the 401k Plan. Non-represented employees hired on or after January 1, 2014, and IBEW-represented employees hired on or after December 12, 2014, will have access to the 401(k) plan and will choose how they want to accumulate funds for retirement, with two contribution sources from PSE:
	•	401(k) Company Matching: New non-represented, UA-represented and IBEW-represented employees will receive company match each paycheck based on a new schedule-100% match on the first 3% of pay contributed and 50% match on the next 3% of pay contributed. An employee who contributes 6% of pay will receive 4.5% of pay in company match. Company matching will be immediately vested.
	•	Company Contribution: New UA-represented employees will receive an annual company contribution of 4% of eligible pay placed in the Cash Balance retirement plan. New non-represented and IBEW-represented employees will receive an annual company contribution of 4% of eligible pay, placed either in the Investment Plan 401(k) plan or in PSE’s Retirement Plan (Cash Balance retirement plan). New non-represented and IBEW-represented employees will make a one-time election within 30 days of hire and direct that PSE put the 4% contribution either into the 401(k) plan or into an account in the Cash Balance retirement plan. The Company’s 4% contribution will vest after three years of service.

Retirement_Benefits

Retirement Benefits	12 Months Ended
	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Retirement Benefits	Retirement Benefits
	PSE has a defined benefit pension plan covering substantially all PSE employees.  Pension benefits earned are a function of age, salary, years of service and, in the case of employees in the cash balance formula plan, the applicable annual interest crediting rates.  Beginning in 2014, all new UA employees and those new non-represented employees who elect to accumulate the Company contribution in the Cash Balance pension, (effective January 1, 2014) and all new IBEW (effective December 12, 2014), will receive annual pay credits of 4% each year. They will also receive interest credits like other participants in the Cash Balance pension, which are at least 1% per quarter. When a newly-hired employee with a vested Cash Balance benefit leaves PSE, he or she will have annuity and lump sum options for distribution, with annuities calculated according to the Pension Protection Act. Those who select the lump sum option will receive their current cash balance amount. Participation by continuing employees in the Cash Balance pension plan is not affected. PSE also maintains a non-qualified Supplemental Executive Retirement Plan (SERP) for its key senior management employees.
	In addition to providing pension benefits, PSE provides group health care and life insurance benefits for certain retired employees.  These benefits are provided principally through an insurance company.  The insurance premiums, paid primarily by retirees, are based on the benefits provided during the year.
	The 2009 merger of Puget Energy with Puget Holdings triggered a new basis of accounting for PSE’s retirement benefit plans in the Puget Energy consolidated financial statements.  Such purchase accounting adjustments associated with the re-measurement of the retirement plans are recorded at Puget Energy.
	The following tables summarize the Company’s change in benefit obligation, change in plan assets and amounts recognized in the Statements of Financial Position for the years ended December 31, 2014 and 2013:
	Puget Energy and	Qualified						SERP						Other
	Puget Sound Energy	Pension Benefits						Pension Benefits						Benefits
	(Dollars in Thousands)	2014			2013			2014			2013			2014			2013
	Change in benefit obligation:
	Benefit obligation at beginning of period	$	573,317		$	616,290		$	47,279		$	51,795		$	14,939		$	17,672
	Service cost	17,437			19,285			1,042			1,498			112			134
	Interest cost	28,039			24,754			2,310			2,045			684			664
	Amendment	—			—			—			478			—			—
	Actuarial loss (gain)	104,618			(48,559		)	7,162			(1,687		)	1,108			(2,240		)
	Benefits paid	(33,217		)	(38,453		)	(1,938		)	(6,850		)	(1,424		)	(1,536		)
	Medicare part D subsidy received	—			—			—			—			269			245
	Benefit obligation at end of period	$	690,194		$	573,317		$	55,855		$	47,279		$	15,688		$	14,939
	Puget Energy and	Qualified						SERP						Other
	Puget Sound Energy	Pension Benefits						Pension Benefits						Benefits
	(Dollars in Thousands)	2014			2013			2014			2013			2014			2013
	Change in plan assets:
	Fair value of plan assets at beginning of period	$	615,721		$	531,183		$	—		$	—		$	8,774		$	7,541
	Actual return on plan assets	25,669			102,591			—			—			522			1,861
	Employer contribution	18,000			20,400			1,938			6,850			488			908
	Benefits paid	(33,217		)	(38,453		)	(1,938		)	(6,850		)	(1,424		)	(1,536		)
	Fair value of plan assets at end of period	$	626,173		$	615,721		$	—		$	—		$	8,360		$	8,774
	Funded status at end of period	$	(64,021	)	$	42,404		$	(55,855	)	$	(47,279	)	$	(7,328	)	$	(6,165	)
	Puget Energy and	Qualified						SERP						Other
	Puget Sound Energy	Pension Benefits						Pension Benefits						Benefits
	(Dollars in Thousands)	2014			2013			2014			2013			2014			2013
	Amounts recognized in Statement of Financial Position consist of:
	Noncurrent assets	$	—		$	42,404		$	—		$	—		$	—		$	—
	Current liabilities	—			—			(4,386		)	(3,981		)	(355		)	(421		)
	Noncurrent liabilities	(64,021		)	—			(51,469		)	(43,298		)	(6,973		)	(5,744		)
	Net assets (liabilities)	$	(64,021	)	$	42,404		$	(55,855	)	$	(47,279	)	$	(7,328	)	$	(6,165	)
	Puget Energy and	Qualified						SERP						Other
	Puget Sound Energy	Pension Benefits						Pension Benefits						Benefits
	(Dollars in Thousands)	2014			2013			2014			2013			2014			2013
	Pension Plans with an Accumulated Benefit Obligation in excess of Plan Assets:
	Project benefit obligation	$	690,194		$	573,317		$	55,855		$	47,279		$	15,688		$	14,939
	Accumulated benefit obligation	681,745			566,689			50,137			40,892			15,553			14,794
	Fair value of plan assets	$	626,173		$	615,721		$	—		$	—		$	8,360		$	8,774
	The following tables summarize Puget Energy and Puget Sound Energy's pension benefit amounts recognized in Accumulated Other Comprehensive income for the years ended December 31, 2014 and 2013:
	Puget Energy	Qualified						SERP						Other
		Pension Benefits						Pension Benefits						Benefits
	(Dollars in Thousands)	2014			2013			2014			2013			2014			2013
	Amounts recognized in Accumulated Other Comprehensive Income consist of:
	Net loss (gain)	$	55,471		$	(65,943	)	$	15,918		$	9,670		$	(1,457	)	$	(2,972	)
	Prior service cost (credit)	(13,782		)	(15,762		)	331			373			—			—
	Total	$	41,689		$	(81,705	)	$	16,249		$	10,043		$	(1,457	)	$	(2,972	)
	Puget Sound Energy	Qualified						SERP						Other
		Pension Benefits						Pension Benefits						Benefits
	(Dollars in Thousands)	2014			2013			2014			2013			2014			2013
	Amounts recognized in Accumulated Other Comprehensive Income consist of:
	Net loss (gain)	$	247,331		$	138,324		$	19,751		$	14,050		$	(3,733	)	$	(5,556	)
	Prior service cost (credit)	(10,952		)	(12,525		)	339			383			3			6
	Total	$	236,379		$	125,799		$	20,090		$	14,433		$	(3,730	)	$	(5,550	)
	The following tables summarize Puget Energy's and Puget Sound Energy's net periodic benefit cost for the years ended December 31, 2014, 2013 and 2012:
	Puget Energy	Qualified									SERP									Other
		Pension Benefits									Pension Benefits									Benefits
	(Dollars in Thousands)	2014			2013			2012			2014			2013			2012			2014			2013			2012
	Components of net periodic benefit cost:
	Service cost	$	17,437		$	19,285		$	16,926		$	1,042		$	1,498		$	1,073		$	112		$	134		$	139
	Interest cost	28,039			24,754			25,986			2,310			2,045			2,152			684			664			751
Expected return on plan assets	(42,464		)	(39,095		)	(36,203		)	—			—			—			(535		)	(436		)	(435		)
Amortization of prior service cost (credit)	(1,980		)	(1,980		)	(1,980		)	42			(17		)	—			—			—			—
Amortization of net loss	—			2,889			768			913			1,461			702			(393		)	69			53
Net periodic benefit cost	$	1,032		$	5,853		$	5,497		$	4,307		$	4,987		$	3,927		$	(132	)	$	431		$	508
Puget Sound Energy	Qualified									SERP									Other
	Pension Benefits									Pension Benefits									Benefits
(Dollars in Thousands)	2014			2013			2012			2014			2013			2012			2014			2013			2012
Components of net periodic benefit cost:
Service cost	$	17,437		$	19,285		$	16,926		$	1,042		$	1,498		$	1,073		$	112		$	134		$	139
Interest cost	28,039			24,753			25,986			2,310			2,045			2,152			684			664			751
Expected return on plan assets	(43,252		)	(40,685		)	(41,533		)	—			—			—			(535		)	(436		)	(435		)
Amortization of prior service cost (credit)	(1,573		)	(1,573		)	(1,573		)	44			(16		)	293			3			30			35
Amortization of net loss(gain)	13,195			20,612			15,015			1,461			2,191			1,432			(702		)	(284		)	(245		)
Amortization of transition obligation	—			—			—			—			—			—			—			—			50
Net periodic benefit cost	$	13,846		$	22,392		$	14,821		$	4,857		$	5,718		$	4,950		$	(438	)	$	108		$	295
The following tables summarize Puget Energy's and Puget Sound Energy's benefit obligations recognized in other comprehensive income for the years ended December 31, 2014 and 2013:
Puget Energy	Qualified						SERP						Other
	Pension Benefits						Pension Benefits						Benefits
(Dollars in Thousands)	2014			2013			2014			2013			2014			2013
Other changes (pre-tax) in plan assets and benefit obligations recognized in other comprehensive income:
Net loss (gain)	$	121,413		$	(112,055	)	$	7,162		$	(1,687	)	$	1,121		$	(3,665	)
Amortization of net loss (gain)	—			(2,889		)	(913		)	(1,461		)	394			(70		)
Prior service credit	—			—			—			478			—			—
Amortization of prior service credit	1,980			1,980			(42		)	17			—			—
Total change in other comprehensive income for year	$	123,393		$	(112,964	)	$	6,207		$	(2,653	)	$	1,515		$	(3,735	)
Puget Sound Energy	Qualified						SERP						Other
	Pension Benefit						Pension Benefits						Benefits
(Dollars in Thousands)	2014			2013			2014			2013			2014			2013
Other changes (pre-tax) in plan assets and benefit obligations recognized in other comprehensive income:
Net loss (gain)	$	122,202		$	(110,465	)	$	7,162		$	(1,687	)	$	1,121		$	(3,665	)
Amortization of net (loss) gain	(13,195		)	(20,612		)	(1,461		)	(2,191		)	702			284
Prior service cost (credit)	—			—			—			477			—			—
Amortization of prior service cost (credit)	1,573			1,573			(44		)	16			(3		)	(30		)
Amortization of transition obligation	—			—			—			—			—			—
Total change in other comprehensive income for year	$	110,580		$	(129,504	)	$	5,657		$	(3,385	)	$	1,820		$	(3,411	)
The estimated prior service cost (credit) for the pension plans that will be amortized from accumulated OCI into net periodic benefit cost in 2015 by Puget Energy is $3.9 million.  The estimated net (loss) gain for the SERP that will be amortized from accumulated OCI into net periodic benefit cost in 2015 is $1.6 million. The estimated prior service cost (credit) for the SERP that will be amortized from accumulated OCI into net periodic benefit cost in 2015 is immaterial.  The estimated net (loss) gain, prior service cost (credit) and transition (obligation) asset for the other postretirement plans that will be amortized from accumulated OCI into net periodic benefit cost in 2015 are immaterial.
The estimated net (loss) gain and prior service cost (credit) for the pension plans that will be amortized from accumulated OCI into net periodic benefit cost in 2015 by Puget Sound Energy are $20.5 million and $1.6 million, respectively.  The estimated net loss (gain) and prior service cost (credit) for the SERP that will be amortized from accumulated OCI into net periodic benefit cost in 2015 are $2.1 million. The estimated prior service cost (credit) for the SERP that will be amortized from accumulated OCI into net periodic benefit cost in 2015 is immaterial.  The estimated net (loss) gain for the other postretirement plan that will be amortized from accumulated OCI into net periodic benefit cost in 2015 is $0.3 million and prior service cost (credit) and transition (obligation) asset for the other postretirement plans are immaterial.
The aggregate expected contributions by the Company to fund the qualified pension plan, SERP and the other postretirement plans for the year ending December 31, 2015 are expected to be at least $18.0 million, $4.4 million and $0.5 million, respectively.
Assumptions
In accounting for pension and other benefit obligations and costs under the plans, the following weighted-average actuarial assumptions were used by the Company:
	Qualified						SERP						Other
	Pension Benefits						Pension Benefits						Benefits
Benefit Obligation Assumptions	2014		2013		2012		2014		2013		2012		2014		2013		2012
Discount rate 1	4.25	%	5.1	%	4.15	%	4.25	%	5.1	%	4.15	%	4.25	%	5.1	%	4.15	%
Rate of compensation increase	4.5	%	4.5	%	4.5	%	4.5	%	4.5	%	4.5	%	4.5	%	4.5	%	4.5	%
Medical trend rate	—		—		—		—		—		—		5.7	%	6.8	%	7.5	%
Benefit Cost Assumptions
Discount rate	5.1	%	4.15	%	4.75	%	5.1	%	4.15	%	4.75	%	5.1	%	4.15	%	4.75	%
Rate of plan assets	7.75	%	7.75	%	7.75	%	—		—		—		7	%	6.9	%	7.5	%
Rate of compensation increase	4.5	%	4.5	%	4.5	%	4.5	%	4.5	%	4.5	%	4.5	%	4.5	%	4.5	%
Medical trend rate	—		—		—		—		—		—		6.7	%	8.2	%	7.5	%
_______________
1	The Company calculates the present value of the pension liability using a discount rate of 4.25% which represents the single-rate equivalent of the AA rated corporate bond yield curve.
The assumed medical inflation rate used to determine benefit obligations is 6.70% in 2015 grading down to 4.30% in 2016.  A 1.0% change in the assumed medical inflation rate would have the following effects:
	2014						2013
(Dollars in Thousands)	1% Increase			1% Decrease			1% Increase			1% Decrease
Effect on post-retirement benefit obligation	$	47		$	(47	)	$	66		$	(66	)
Effect on service and interest cost components	2			(2		)	3			(3		)
The Company has selected the expected return on plan assets based on a historical analysis of rates of return and the Company’s investment mix, market conditions, inflation and other factors.  The expected rate of return is reviewed annually based on these factors.  The Company’s accounting policy for calculating the market-related value of assets for the Company’s retirement plan is as follows.  PSE market-related value of assets is based on a five-year smoothing of asset gains (losses) measured from the expected return on market-related assets.  This is a calculated value that recognizes changes in fair value in a systematic and rational manner over five years.  The same manner of calculating market-related value is used for all classes of assets, and is applied consistently from year to year.
Puget Energy’s pension and other postretirement benefits income or costs depend on several factors and assumptions, including plan design, timing and amount of cash contributions to the plan, earnings on plan assets, discount rate, expected long-term rate of return, mortality and health care costs trends.  Changes in any of these factors or assumptions will affect the amount of income or expense that Puget Energy records in its financial statements in future years and its projected benefit obligation.  Puget Energy has selected an expected return on plan assets based on a historical analysis of rates of return and Puget Energy’s investment mix, market conditions, inflation and other factors.  As required by merger accounting rules, market-related value was reset to market value effective with the merger.
The discount rates were determined by using market interest rate data and the weighted-average discount rate from Citigroup Pension Liability Index Curve.  The Company also takes into account in determining the discount rate the expected changes in market interest rates and anticipated changes in the duration of the plan liabilities.
Plan Benefits
The expected total benefits to be paid under the next five years and the aggregate total to be paid for the five years thereafter are as follows:
(Dollars in Thousands)	2015			2016			2017			2018			2019			2020-2024
Qualified Pension total benefits	$	41,100		$	41,400		$	42,100		$	43,300		$	43,900		$	237,300
SERP Pension total benefits	$	4,386		$	2,595		1,940			5,346			5,811			18,759
Other Benefits total with Medicare Part D subsidy	$	1,080		$	1,136		$	1,113		$	1,085		$	1,062		$	5,935
Other Benefits total without Medicare Part D subsidy	$	1,429		$	1,414		$	1,398		$	1,380		$	1,362		$	6,340
Plan Assets
Plan contributions and the actuarial present value of accumulated plan benefits are prepared based on certain assumptions pertaining to interest rates, inflation rates and employee demographics, all of which are subject to change.  Due to uncertainties inherent in the estimations and assumptions process, changes in these estimates and assumptions in the near term may be material to the financial statements.
The Company has a Retirement Plan Committee that establishes investment policies, objectives and strategies designed to balance expected return with a prudent level of risk.  All changes to the investment policies are reviewed and approved by the Retirement Plan Committee prior to being implemented.
The Retirement Plan Committee invests trust assets with investment managers who have historically achieved above-median long-term investment performance within the risk and asset allocation limits that have been established.  Interim evaluations are routinely performed with the assistance of an outside investment consultant.  To obtain the desired return needed to fund the pension benefit plans, the Retirement Plan Committee has established investment allocation percentages by asset classes as follows:
	Allocation
Asset Class	Minimum	Target	Maximum
Domestic large cap equity	25%	31%	40%
Domestic small cap equity	0%	9%	15%
Non-U.S. equity	10%	25%	30%
Fixed income	15%	25%	30%
Real estate	0%	0%	10%
Absolute return	5%	10%	15%
Cash	0%	0%	5%
Plan Fair Value Measurements
ASC 715, “Compensation – Retirement Benefits” (ASC 715) directs companies to provide additional disclosures about plan assets of a defined benefit pension or other postretirement plan.  The objectives of the disclosures are to disclose the following: (1) how investment allocation decisions are made, including the factors that are pertinent to an understanding of investment policies and strategies; (2) major categories of plan assets; (3) inputs and valuation techniques used to measure the fair value of plan assets; (4) effect of fair value measurements using significant unobservable inputs (Level 3) on changes in plan assets for the period; and (5) significant concentrations of risk within plan assets.
ASC 820 allows the reporting entity, as a practical expedient, to measure the fair value of investments that do not have readily determinable fair values on the basis of the net asset value per share of the investment if the net asset value of the investment is calculated in a matter consistent with ASC 946, “Financial Services – Investment Companies.”  The standard requires disclosures about the nature and risk of the investments and whether the investments are probable of being sold at amounts different from the net asset value per share.
The following table sets forth by level, within the fair value hierarchy, the qualified pension plan as of December 31, 2014 and 2013:
	Recurring Fair Value Measures												Recurring Fair Value Measures
	As of December 31, 2014												As of December 31, 2013
(Dollars in Thousands)	Level 1			Level 2			Level 3			Total			Level 1			Level 2			Level 3			Total
Assets:
Equities:
Non-US equity 1	$	71,026		$	74,131		$	—		$	145,157		$	76,188		$	78,816		$	—		$	155,004
Domestic large cap equity 2	134,765			68,336			—			203,101			157,874			35,851			—			193,725
Domestic small cap equity 3	59,657			—			—			59,657			62,867			—			—			62,867
Total equities	265,448			142,467			—			407,915			296,929			114,667			—			411,596
Tactical asset allocation 4	—			—			—			—			—			—			—			—
Fixed income securities 5	72,331			67,182			—			139,513			135,007			—			—			135,007
Absolute return 6	—			—			65,251			65,251			—			—			62,278			62,278
Cash and cash equivalents 7	12,650			—			—			12,650			—			7,054			—			7,054
Subtotal	$	350,429		$	209,649		$	65,251		$	625,329		$	431,936		$	121,721		$	62,278		$	615,935
Net (payable) receivable	—			—			—			844			—			—			—			(417		)
Accrued income	—			—			—			—			—			—			—			203
Total assets										$	626,173											$	615,721
_________________
1	Non – US Equity investments are comprised of a (1) mutual fund; and a (2) commingled fund.  The investment in the mutual fund is valued using quoted market prices multiplied by the number of shares owned as of December 31, 2014.  The investment in the commingled fund is valued at the net asset value per share multiplied by the number of shares held as of December 31, 2014.
2	Domestic large cap equity investments are comprised of (1) common stock, and a (2) commingled fund.  Investments in common stock are valued using quoted market prices multiplied by the number of shares owned as of December 31, 2014.  The investment in the commingled fund is valued at the net asset value per share multiplied by the number of shares held as of December 31, 2014.
3	Domestic small cap equity investments are comprised of (1) common stock and a (2) mutual fund. The investments in common stock are valued using quoted market prices multiplied by the number of shares owned as of December 31, 2014. The investment in the mutual fund is valued using quoted market prices multiplied by the number of shares owned as of December 31, 2014.
4	The tactical asset allocation investment is comprised of a commingled fund, which is valued at the net asset value per share multiplied by the number of shares held as of the measurement date.
5	Fixed income securities consist of a mutual fund.  The investment in the mutual fund is valued using quoted market prices multiplied by the number of shares owned as of December 31, 2014.
6	As of December 31, 2014 absolute return investments consist of two partnerships.  The partnerships are valued using the financial reports as of December 31, 2014.  These investments are a Level 3 under ASC 820 because the significant valuation inputs are primarily internal to the partnerships with little third party involvement.
7	The investment consists of a money market fund, which is valued at the net asset value per share of $1.00 per unit as of December 31, 2014.  The money market fund invests primarily in commercial paper, notes, repurchase agreements, and other evidences of indebtedness which are payable on demand or short-term in nature.
Level 3 Roll-Forward
The following table sets forth a reconciliation of changes in the fair value of the plan’s Level 3 assets:
	As of December 31, 2014									As of December 31, 2013
(Dollars in Thousands)	Partnership			Mutual Funds			Total			Partnership			Mutual Funds			Total
Balance at beginning of year	$	62,278		$	—		$	62,278		$	55,614		$	—		$	55,614
Additional investments	—			—			—			—			—			—
Distributions	—			—			—			—			—			—
Realized losses on distributions	—			—			—			—			—			—
Unrealized gains relating to instruments still held at the reporting date	2,973			—			2,973			6,664			—			6,664
Transferred out of level 3 1	—			—			—			—			—			—
Balance at end of year	$	65,251		$	—		$	65,251		$	62,278		$	—		$	62,278
_________________
1	The plan had no transfers between level 2 and level 1 during the years ended December 31, 2014 or 2013.
The following table sets forth by level, within the fair value hierarchy, the Other Benefits plan assets which consist of insurance benefits for retired employees, at fair value:
	Recurring Fair Value Measures									Recurring Fair Value Measures
	As of December 31, 2014									As of December 31, 2013
(Dollars in Thousands)	Level 1			Level 2			Total			Level 1			Level 2			Total
Assets:
Mutual fund 1	$	8,301		$	—		$	8,301		$	8,703		$	—		$	8,703
Cash equivalents 2	59			—			59			—			71			71
Total assets	$	8,360		$	—		$	8,360		$	8,703		$	71		$	8,774
_______________
1	This is a publicly traded balanced mutual fund.  The fund seeks regular income, conservation of principal, and an opportunity for long-term growth of principal and income.  The fair value is determined by taking the number of shares owned by the plan, and multiplying by the market price as of December 31, 2014.
2	This is a money market fund.  The money market fund investments are valued at the net asset value per share of $1.00 per unit as of December 31, 2014.  The money market fund invests primarily in commercial paper, notes, repurchase agreements, and other evidences of indebtedness which are payable on demand or short-term in nature.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes
	The details of income tax (benefit) expense are as follows:
	Puget Energy	Year Ended December 31,
	(Dollars in Thousands)	2014			2013			2012
	Charged to operating expenses:
	Current:
	Federal	$	—		$	—		$	4,268
	State	—			—			—
	Deferred:
	Federal	57,152			122,559			100,701
	State	(167		)	(151		)	(244		)
	Total income tax expense	$	56,985		$	122,408		$	104,725
	Puget Sound Energy	Year Ended December 31,
	(Dollars in Thousands)	2014			2013			2012
	Charged to operating expenses:
	Current:
	Federal	$	—		$	—		$	4,268
	State	—			—			—
	Deferred:
	Federal	89,342			160,886			145,040
	State	—			—			—
	Total income tax expense	$	89,342		$	160,886		$	149,308
	The following reconciliation compares pre-tax book income at the federal statutory rate of 35.0% to the actual income tax expense in the Statements of Income:
	Puget Energy	Year Ended December 31,
	(Dollars in Thousands)	2014			2013			2012
	Income taxes at the statutory rate	$	80,087		$	142,847		$	132,491
	Increase (decrease):
	Production tax credit	(23,073		)	(22,414		)	(22,188		)
	AFUDC excluded from taxable income	(3,790		)	(9,406		)	(16,543		)
	Capitalized interest	2,947			7,294			9,757
	Utility plant differences	7,090			9,527			8,674
	Treasury grant amortization	(8,808		)	(7,651		)	(1,007		)
	Tenaska gas contract	—			1			(4,687		)
	Other - net	2,532			2,210			(1,772		)
	Total income tax expense	$	56,985		$	122,408		$	104,725
	Effective tax rate	24.9		%	30		%	27.7		%
	Puget Sound Energy	Year Ended December 31,
	(Dollars in Thousands)	2014			2013			2012
	Income taxes at the statutory rate	$	114,084		$	180,955		$	176,917
	Increase (decrease):
	Production tax credit	(23,073		)	(22,414		)	(22,188		)
	AFUDC excluded from taxable income	(3,790		)	(9,406		)	(16,543		)
	Capitalized interest	2,947			7,294			9,757
	Utility plant differences	7,090			9,527			8,674
	Treasury grant amortization	(8,808		)	(7,651		)	(1,007		)
	Tenaska gas contract	—			1			(4,687		)
	Other - net	892			2,580			(1,615		)
	Total income tax expense	$	89,342		$	160,886		$	149,308
	Effective tax rate	27.4		%	31.1		%	29.5		%
	The Company’s deferred tax liability at December 31, 2014 and 2013 is composed of amounts related to the following types of temporary differences:
	Puget Energy	At December 31,
	(Dollars in Thousands)	2014			2013
	Utility plant and equipment	$	1,720,730		$	1,625,107
	Regulatory asset for income taxes	95,432			146,867
	Fair value of debt instruments	73,606			76,991
	Other deferred tax liabilities	200,124			202,189
	Subtotal deferred tax liabilities	2,089,892			2,051,154
	Net operating loss carryforward	(417,684		)	(374,606		)
	Production tax credit carryforward	(158,604		)	(135,531		)
	Regulatory liability on production tax credit	(84,344		)	(71,880		)
	Fair value of derivative instruments	(36,227		)	(7,166		)
	Other deferred tax assets	(32,121		)	(60,970		)
	Subtotal deferred tax assets	(728,980		)	(650,153		)
	Total	$	1,360,912		$	1,401,001
Puget Sound Energy	At December 31,
(Dollars In Thousands)	2014			2013
Utility plant and equipment	$	1,720,730		$	1,625,107
Regulatory asset for income taxes	94,913			146,350
Other deferred tax liabilities	171,380			131,977
Subtotal deferred tax liabilities	1,987,023			1,903,434
Net operating loss carryforward	(181,514		)	(173,068		)
Production tax credit carryforward	(158,604		)	(135,531		)
Regulatory liability on production tax credit	(84,344		)	(71,880		)
Fair value of derivative instruments	(39,067		)	(9,988		)
Other deferred tax assets	(82,084		)	(69,175		)
Subtotal deferred tax assets	(545,613		)	(459,642		)
Total	$	1,441,410		$	1,443,792
The above amounts have been classified in the Consolidated Balance Sheets as follows:
Puget Energy	At December 31
(Dollars in Thousands)	2014			2013
Current deferred taxes	$	(161,445	)	$	(86,004	)
Non-current deferred taxes	1,522,357			1,487,005
Total	$	1,360,912		$	1,401,001
Puget Sound Energy	At December 31
(Dollars in Thousands)	2014			2013
Current deferred taxes	$	(208,447	)	$	(141,058	)
Non-current deferred taxes	1,649,857			1,584,850
Total	$	1,441,410		$	1,443,792
The Company calculates its deferred tax assets and liabilities under ASC 740, “Income Taxes” (ASC 740).  ASC 740 requires recording deferred tax balances, at the currently enacted tax rate, on assets and liabilities that are reported differently for income tax purposes than for financial reporting purposes.  The utilization of deferred tax assets requires sufficient taxable income in future years.  ASC 740 requires a valuation allowance on deferred tax assets when it is more likely than not that the deferred tax assets will not be realized.  The Company’s PTC carryforwards expire from 2026 through 2034.  The Company’s net operating loss carryforwards expire from 2029 through 2034.
For ratemaking purposes, deferred taxes are not provided for certain temporary differences.  PSE has established a regulatory asset for income taxes recoverable through future rates related to those temporary differences for which no deferred taxes have been provided, based on prior and expected future ratemaking treatment.
The Company accounts for uncertain tax position under ASC 740, which clarifies the accounting for uncertainty in income taxes recognized in the financial statements.  ASC 740 requires the use of a two-step approach for recognizing and measuring tax positions taken or expected to be taken in a tax return.  First, a tax position should only be recognized when it is more likely than not, based on technical merits, that the position will be sustained upon challenge by the taxing authorities and taken by management to the court of last resort.  Second, a tax position that meets the recognition threshold should be measured at the largest amount that has a greater than 50.0% likelihood of being sustained.
As of December 31, 2014 and 2013, the Company had no material unrecognized tax benefits.  As a result, no interest or penalties were accrued for unrecognized tax benefits during the year.
For ASC 740 purposes, the Company has open tax years from 2010 through 2014.  The Company classifies interest as interest expense and penalties as other expense in the financial statements.

Litigation

Litigation	12 Months Ended
	Dec. 31, 2014
Litigation Disclosure [Abstract]
Litigation	Litigation
	Colstrip
	PSE has a 50% ownership interest in Colstrip Units 1 and 2, and a 25% interest in Colstrip Units 3 and 4. On March 6, 2013, Sierra Club and Montana Environmental Information Center (MEIC) filed a Clean Air Act citizen suit against all Colstrip owners (including PSE) alleging numerous claims for relief, most of which relate to alleged prevention of significant deterioration (PSD) violations. One claim relates to the alleged failure to update the Title V permit to reflect the major modifications alleged in the first thirty-six claim, another claim alleges that the previous Title V compliance certifications have been incomplete because they did not address the alleged major modifications, and the last claim alleges opacity violations since 2007. The lawsuit was filed in U.S. District of Montana, Billings Division, requesting injunctive relief and civil penalties, including a request that the owners remediate environmental damage and that $100,000 of the civil penalties be used for beneficial mitigation projects.  Discovery in the case is ongoing, and it has been bifurcated into separate liability and remedy trials. The liability trial is currently set for November 2015, and a date for the remedy trial has yet to be determined. PSE is litigating the allegations set forth in the notices, and as such, it is not reasonably possible to estimate the outcome of this matter.
	Other Proceedings
	The Company is also involved in litigation relating to claims arising out of its operations in the normal course of business.  The Company has recorded reserves of $1.7 million and $1.4 million relating to these claims as of December 31, 2014 and 2013, respectively.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies
	For the year ended December 31, 2014, approximately 14.9% of the Company’s energy output was obtained at an average cost of approximately $0.021 per Kilowatt Hour (kWh) through long-term contracts with three of the Washington Public Utility Districts (PUDs) that own hydroelectric projects on the Columbia River.  The purchase of power from the Columbia River projects is on a pro rata share basis under which the Company pays a proportionate share of the annual debt service, operating and maintenance costs and other expenses associated with each project in proportion to the contractual shares that PSE obtains from that project.  In these instances, PSE’s payments are not contingent upon the projects being operable; therefore, PSE is required to make the payments even if power is not delivered.  These projects are financed through substantially level debt service payments and their annual costs should not vary significantly over the term of the contracts unless additional financing is required to meet the costs of major maintenance, repairs or replacements, or license requirements.  The Company’s share of the costs and the output of the projects is subject to reduction due to various withdrawal rights of the PUDs and others over the contract lives.
	The Company's expenses under these PUD contracts were as follows for the years ended December 31:
	(Dollars in Thousands)				2014			2013			2012
	PUD contract costs				$	69,661		$	63,365		$	70,188
	As of December 31, 2014, the Company purchased portions of the power output of the PUDs' projects as set forth in the following table:
			Company's Current Share of
	(Dollars in Thousands)	Contract	Percent of		Megawatt Capacity		Estimated 2015 Costs			2015 Debt Service Costs			Interest included in 2015 Debt Service Costs			Debt Outstanding
		Expiration	Output
	Chelan County PUD:
	Rock Island Project	2031	25	%	156		$	29,854		$	11,009		$	6,174		$	98,191
	Rocky Reach Project	2031	25	%	325		27,583			8,245			3,343			53,299
	Douglas County PUD:
	Wells Project	2018	29.9	%	251		17,277			9,383			2,597			64,931
	Grant County PUD:
	Priest Rapids Development	2052	0.6	%	8		3,689			2,087			1,245			19,828
	Wanapum Development	2052	0.6	%	9		3,689			2,087			1,245			19,828
	Total				749		$	82,092		$	32,811		$	14,604		$	256,077
	The following table summarizes the Company’s estimated payment obligations for power purchases from the Columbia River projects, contracts with other utilities and contracts with non-utilities.  These contracts have varying terms and may include escalation and termination provisions.
	(Dollars in Thousands)	2015			2016			2017			2018			2019			Thereafter		Total
	Columbia River projects	$	73,023		$	75,360		$	74,851		$	65,981		$	53,837		$	644,666	$	987,718
	Other utilities	16,136			18,884			11,823			1,257			890			—		48,990
	Non-utility contracts	117,372			153,863			199,056			204,292			209,699			1,354,191		2,238,473
	Total	$	206,531		$	248,107		$	285,730		$	271,530		$	264,426		$	1,998,857	$	3,275,181
	Total purchased power contracts provided the Company with approximately 12.1 million, 10.7 million and 6.1 million MWhs of firm energy at a cost of approximately $401.4 million, $348.7 million and $203.1 million for the years 2014, 2013 and 2012, respectively.
	The Company has natural gas-fired generation facility obligations for natural gas supply amounting to an estimated $63.6 million in 2015.  Longer term agreements for natural gas supply amount to an estimated $286.7 million for 2016 through 2019.
	PSE enters into short-term energy supply contracts to meet its core customer needs.  These contracts are sometimes classified as NPNS, however in most cases recorded at fair value in accordance with ASC 815.  Commitments under these contracts are $105.8 million, $32.4 million and $6.5 million in 2015, 2016 and 2017, respectively.
	Natural Gas Supply Obligations
	The Company has also entered into various firm supply, transportation and storage service contracts in order to ensure adequate availability of natural gas supply for its firm customers.  The transportation and storage contracts, which have remaining terms from less than one year to 30 years, provide that the Company must pay a fixed demand charge each month, regardless of actual usage.  The Company contracts for its long-term natural gas supply on a firm basis, which means the Company has a 100% daily take obligation and the supplier has a 100% daily delivery obligation to ensure service to PSE’s customers and generation requirements.  The Company incurred demand charges in 2014 for firm transportation service and firm storage and peaking service of $155.0 million and $6.6 million, respectively.  The demand charge for firm natural gas supply was immaterial in 2014. The Company incurred demand charges in 2014 for firm transportation and firm storage service for the natural gas supply for its combustion turbines in the amount of $35.7 million, which is included in the total Company demand charges.
	The following table summarizes the Company’s obligations for future demand charges through the primary terms of its existing contracts.  The quantified obligations are based on the FERC and NEB (National Energy Board) currently authorized rates, which are subject to change.
	Demand Charge Obligations	2015			2016			2017			2018			2019			Thereafter		Total
	(Dollars in Thousands)
	Firm transportation service	$	154,121		$	147,424		$	144,751		$	131,484		$	112,249		$	373,958	$	1,063,987
	Firm storage service	6,528			5,337			5,209			1,407			1,535			1,258		21,274
	Total	$	160,649		$	152,761		$	149,960		$	132,891		$	113,784		$	375,216	$	1,085,261
	Service Contracts
	The following table summarizes the Company’s estimated obligations for service contracts through the terms of its existing contracts.
	Service Contract Obligations	2015			2016			2017			2018			2019			Thereafter		Total
	(Dollars in Thousands)
	Energy production service contracts	$	32,979		$	15,650		$	5,558		$	4,064		$	2,372		$	23,443	$	84,066
	Automated meter reading system	25,402			16,081			13,362			13,996			14,602			51,986		135,429
	Total	$	58,381		$	31,731		$	18,920		$	18,060		$	16,974		$	75,429	$	219,495
	Other Contingencies
	For information regarding PSE's environmental remediation obligations, see Note 3 Regulation and Rates.

Related_Party_Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2014
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions
	On October 10, 2014, U.S. Bancorp announced the appointment of Kimberly Harris to its board of directors effective October 20, 2014.  Ms. Harris is the president and chief executive officer of both Puget Energy and PSE.  U.S. Bancorp is the parent company of U.S. Bank N.A., which directly or through its subsidiaries or affiliates provides credit, banking, investment and trust services to both Puget Energy and PSE.  For the year ended December 31, 2014, Puget Energy and PSE paid a total of approximately $1.0 million in fees and interest to U.S. Bank N.A. and its subsidiaries or affiliates.
	In 2006, PSE entered into a revolving credit facility with Puget Energy in the form of a Demand Promissory Note (Note).  At December 31, 2014 and 2013, the outstanding balance of the Note was $28.9 million and $29.6 million, respectively, and the interest rate was 0.391% and 0.325%, respectively. (See Note 7).

Segment_Information

Segment Information	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Segment Information	Segment Information
	Puget Energy operates one reportable business segment referred to as the regulated utility segment.  Puget Energy’s regulated utility operation generates, purchases and sells electricity and purchases, transports and sells natural gas.  The service territory of PSE covers approximately 6,000 square miles in the state of Washington. In managing the business, management reviews the consolidated financial statements for Puget Energy and PSE during the year.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss)
	The following tables present the changes in the Company’s accumulated other comprehensive income (loss) (AOCI) by component for the years ended December 31, 2014, 2013 and 2012, respectively.
	Puget Energy	Net unrealized gain (loss) and prior service cost on pension plans			Net unrealized gain (loss) on energy derivative instruments			Net unrealized gain (loss) on interest rate swaps
	Changes in AOCI, net of tax
	(Dollars in Thousands)										Total
	Balance at December 31, 2011	$	(15,195	)	$	(1,113	)	$	(14,599	)	$	(30,907	)
	Other comprehensive income (loss) before reclassifications	(13,574		)	—			—			(13,574		)
	Amounts reclassified from accumulated other comprehensive income (loss), net of tax	(296		)	371			11,577			11,652
	Net current-period other comprehensive income (loss)	(13,870		)	371			11,577			(1,922		)
	Balance at December 31, 2012	$	(29,065	)	$	(742	)	$	(3,022	)	$	(32,829	)
	Other comprehensive income (loss) before reclassifications	76,004			—			—			76,004
	Amounts reclassified from accumulated other comprehensive income (loss), net of tax	1,575			37			2,928			4,540
	Net current-period other comprehensive income (loss)	77,579			37			2,928			80,544
	Balance at December 31, 2013	$	48,514		$	(705	)	$	(94	)	$	47,715
	Other comprehensive income (loss) before reclassifications	(84,301		)	—			—			(84,301		)
	Amounts reclassified from accumulated other comprehensive income (loss), net of tax	(923		)	372			94			(457		)
	Net current-period other comprehensive income (loss)	(85,224		)	372			94			(84,758		)
	Balance at December 31, 2014	$	(36,710	)	$	(333	)	$	—		$	(37,043	)
	Puget Sound Energy	Net unrealized gain (loss) and prior service cost on pension plans			Net unrealized gain (loss) on energy derivative instruments			Net unrealized gain (loss) on treasury interest rate swaps
	Changes in AOCI, net of tax
	(Dollars in Thousands)										Total
	Balance at December 31, 2011	$	(168,704	)	$	(12,934	)	$	(6,941	)	$	(188,579	)
	Other comprehensive income (loss) before reclassifications	(17,049		)	—			—			(17,049		)
	Amounts reclassified from accumulated other comprehensive income (loss), net of tax	9,755			8,358			317			18,430
	Net current-period other comprehensive income (loss)	(7,294		)	8,358			317			1,381
	Balance at December 31, 2012	$	(175,998	)	$	(4,576	)	$	(6,624	)	$	(187,198	)
	Other comprehensive income (loss) before reclassifications	74,969			—			—			74,969
	Amounts reclassified from accumulated other comprehensive income (loss), net of tax	13,624			2,549			317			16,490
	Net current-period other comprehensive income (loss)	88,593			2,549			317			91,459
	Balance at December 31, 2013	$	(87,405	)	$	(2,027	)	$	(6,307	)	$	(95,739	)
	Other comprehensive income (loss) before reclassifications	(84,955		)	—			—			(84,955		)
	Amounts reclassified from accumulated other comprehensive income (loss), net of tax	8,079			1,341			317			9,737
	Net current-period other comprehensive income (loss)	(76,876		)	1,341			317			(75,218		)
	Balance at December 31, 2014	$	(164,281	)	$	(686	)	$	(5,990	)	$	(170,957	)
	Details about these reclassifications out of accumulated other comprehensive income (loss) for the years ended December 31, 2014, 2013 and 2012, respectively, are as follows:
	Puget Energy
	(Dollars in Thousands)
	Details about accumulated other comprehensive income (loss) components	Affected line item in the statement where net income (loss) is presented	Amount reclassified from accumulated
			other comprehensive income (loss)
			2014			2013			2012
	Net unrealized gain (loss) and prior service cost on pension plans:
	Amortization of prior service cost	(a)	1,938			1,997			1,980
	Amortization of net gain (loss)	(a)	(519		)	(4,420		)	(1,524		)
		Total before tax	1,419			(2,423		)	456
		Tax (expense) or benefit	(496		)	848			(160		)
		Net of Tax	$	923		$	(1,575	)	$	296
	Net unrealized gain (loss) on energy derivative instruments:
	Commodity contracts: Electric derivatives	Electric generation fuel	—			—			100
		Purchased electricity	(572		)	(57		)	(671		)
		Total before tax	(572		)	(57		)	(571		)
		Tax (expense) or benefit	200			20			200
		Net of Tax	$	(372	)	$	(37	)	$	(371	)
	Net unrealized gain (loss) on interest rate swaps:
	Interest rate contracts	Interest expense	$	(144	)	$	(4,505	)	$	(17,811	)
		Tax (expense) or benefit	50			1,577			6,234
		Net of Tax	$	(94	)	$	(2,928	)	$	(11,577	)
	Total reclassification for the period	Net of Tax	$	457		$	(4,540	)	$	(11,652	)
	__________
	(a)	These accumulated other comprehensive income components are included in the computation of net periodic pension cost (see Note 12 for additional details).
	Puget Sound Energy
	(Dollars in Thousands)
	Details about accumulated other comprehensive income (loss) components	Affected line item in the statement where net income (loss) is presented	Amount reclassified from accumulated
			other comprehensive income (loss)
			2014			2013			2012
Net unrealized gain (loss) and prior service cost on pension plans:
Amortization of prior service cost	(a)	$	1,526		$	1,559		$	1,245
Amortization of net gain (loss)	(a)	(13,954		)	(22,519		)	(16,203		)
Amortization of transition obligation	(a)	—			—			(50		)
	Total before tax	(12,428		)	(20,960		)	(15,008		)
	Tax (expense) or benefit	4,349			7,336			5,253
	Net of tax	$	(8,079	)	$	(13,624	)	$	(9,755	)
Net unrealized gain (loss) on energy derivative instruments:
Commodity contracts: Electric derivatives	Electric generation fuel	—			—			97
	Purchased electricity	(2,063		)	(3,922		)	(12,955		)
	Total before tax	(2,063		)	(3,922		)	(12,858		)
	Tax (expense) or benefit	722			1,373			4,500
	Net of Tax	$	(1,341	)	$	(2,549	)	$	(8,358	)
Net unrealized gain (loss) on treasury interest rate swaps:
Interest rate contracts	Interest expense	(488		)	(488		)	(488		)
	Tax (expense) or benefit	171			171			171
	Net of Tax	$	(317	)	$	(317	)	$	(317	)
Total reclassification for the period	Net of Tax	$	(9,737	)	$	(16,490	)	$	(18,430	)
__________
(a)	These accumulated other comprehensive income components are included in the computation of net periodic pension cost (see Note 12 for additional details).

SUPPLEMENTAL_QUARTERLY_FINANCI

SUPPLEMENTAL QUARTERLY FINANCIAL DATA	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Supplemental Quarterly Financial Data	SUPPLEMENTAL QUARTERLY FINANCIAL DATA
	The following unaudited amounts, in the opinion of the Company, include all adjustments (consisting of normal recurring adjustments) necessary for a fair statement of the results of operations for the interim periods.  Quarterly amounts vary during the year due to the seasonal nature of the utility business.
	Puget Energy	2014 Quarter
	(Unaudited; Dollars in Thousands)	First		Second		Third			Fourth
	Operating revenue	$	1,025,375	$	662,916	$	593,715		$	831,165
	Operating income	236,301		145,266		65,069			131,215
	Net income (loss)	107,592		41,113		(12,958		)	36,088
		2013 Quarter
	(Unaudited; Dollars in Thousands)	First		Second		Third			Fourth
	Operating revenue	$	999,818	$	642,486	$	598,348		$	946,645
	Operating income	317,735		95,081		100,043			242,301
	Net income (loss)	167,475		905		8,540			108,808
	Puget Sound Energy	2014 Quarter
	(Unaudited; Dollars in Thousands)	First		Second		Third			Fourth
	Operating revenue	$	1,025,375	$	662,916	$	593,951		$	833,881
	Operating income	232,977		142,185		62,317			131,214
	Net income (loss)	121,083		57,834		3,057			54,640
		2013 Quarter
	(Unaudited; Dollars in Thousands)	First		Second		Third			Fourth
	Operating revenue	$	999,707	$	642,486	$	598,348		$	946,794
	Operating income	310,587		91,094		96,085			237,808
	Net income (loss)	179,938		26,663		26,605			122,923

SCHEDULE_I_CONDENSED_FINANCIAL

SCHEDULE I CONDENSED FINANCIAL INFORMATION OF PUGET ENERGY	12 Months Ended
	Dec. 31, 2014
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Schedule I: Condensed Financial Information of Puget Energy	SCHEDULE I:  CONDENSED FINANCIAL INFORMATION OF PUGET ENERGY
	Puget Energy
	Condensed Statements of Income and Comprehensive Income (Loss)
	(Dollars in Thousands)
		Year Ended December 31,
		2014			2013			2012
	Non-utility expense and other	$	(5,390	)	$	(1,255	)	$	(2,040	)
	Other income (deductions):
	Equity in earnings of subsidiary (Note 1)	240,102			351,718			365,590
	Unhedged interest rate swap expense	(3,915		)	2,420			(4,288		)
	Interest income	185			114			214
	Interest expense	(93,382		)	(103,372		)	(135,312		)
	Income taxes	34,235			36,103			49,657
	Net income (loss)	171,835			285,728			273,821
	Comprehensive income (loss)	$	87,077		$	366,272		$	271,899
	See accompanying notes to the consolidated financial statements.
	Puget Energy
	Condensed Balance Sheets
	(Dollars in Thousands)
		December 31,
		2014			2013
	Assets:
	Investment in subsidiaries	$	3,337,718		$	3,508,460
	Other property and investments:
	Goodwill	1,656,513			1,656,513
	Current assets:
	Cash	62			191
	Receivables from affiliates 1	28,950			29,605
	Total current assets	29,012			29,796
	Long-term assets:
	Deferred income taxes	267,810			241,787
	Other	15,802			17,992
	Total long-term assets	283,612			259,779
	Total assets	$	5,306,855		$	5,454,548
	Capitalization and liabilities:
	Common equity	$	3,543,328		$	3,679,679
	Long-term debt	1,698,968			1,698,964
	Total capitalization	5,242,296			5,378,643
	Current liabilities:
	Account Payable	130			322
	Interest	23,585			24,047
	Deferred income taxes	31,772			38,296
	Unrealized loss on derivative instruments	6,222			6,584
	Total current liabilities	61,709			69,249
	Long-term liabilities:
	Unrealized loss on derivative instruments	2,850			6,656
	Total long-term liabilities	2,850			6,656
	Commitments and contingencies (Note 3)
	Total capitalization and liabilities	$	5,306,855		$	5,454,548
	_______________
	1	Eliminated in consolidation.
	See accompanying notes to the consolidated financial statements.
	Puget Energy
	Condensed Statements of Cash Flows
	(Dollars in Thousands)
		Year Ended December 31,
		2014			2013			2012
	Operating activities:
	Net income (loss)	$	171,835		$	285,728		$	273,821
	Adjustments to reconcile net income to net cash provided by (used in) operating activities:
	Unrealized gain on derivative instruments	(4,024		)	(3,869		)	(12,984		)
	Deferred income taxes and tax credits - net	(32,597		)	(35,872		)	(49,496		)
	Equity in earnings of subsidiary	(240,102		)	(351,718		)	(365,590		)
	Other	4,758			3,055			11,409
Dividends received from subsidiary	323,424			410,977			175,625
Accounts receivable	(10		)	3			283
Accounts payable	(192		)	110			212
Accrued interest	2,367			(1,299		)	33,842
Net cash provided by (used in) operating activities	225,459			307,115			67,122
Investing activities:
(Increase) decrease in loan to subsidiary	665			—			400
Other	(2,829		)	(1,120		)	(20,901		)
Net cash provided by (used in) investing activities	(2,164		)	(1,120		)	(20,501		)
Financing activities:
Dividends paid	(223,428		)	(170,821		)	(88,594		)
Issuance of bond	—			—			884,000
Redemption of term-loan and other long-term debt	—			(135,000		)	(843,000		)
Issue costs and others	4			5			(5,239		)
Net cash provided by (used in) by financing activities	(223,424		)	(305,816		)	(52,833		)
Increase (decrease) in cash	(129		)	179			(6,212		)
Cash at beginning of year	191			12			6,224
Cash at end of year	$	62		$	191		$	12
See accompanying notes to the consolidated financial statements.
NOTES TO CONDENSED FINANCIAL STATEMENTS
(1) Basis of Presentation
Puget Energy is an energy services holding company that conducts substantially all of its business operations through its subsidiary. These condensed financial statements and related footnotes have been prepared in accordance with Rule 12-04, Schedule I of Regulation S-X. These financial statements, in which Puget Energy’s subsidiary has been included using the equity method, should be read in conjunction with the consolidated financial statements and notes thereto of Puget Energy included in Part II, Item 8 of this Form 10-K. Puget Energy owns 100% of the common stock of its subsidiary.
Equity earnings of subsidiary included earnings from PSE of $236.6 million, $356.1 million and $356.2 million for the years ended December 31, 2014, 2013 and 2012, respectively, and business combination accounting adjustments under ASC 805 recorded at Puget Energy for PSE of $3.5 million, $(4.4) million and $9.4 million for the years ended December 31, 2014, 2013 and 2012, respectively. Investment in subsidiaries includes Puget Energy business combination accounting adjustments under ASC 805 that are recorded at Puget Energy.
(2) Debt
For information concerning Puget Energy’s long-term debt obligations, see Note 6, Long-Term Debt, to the consolidated financial statements of Puget Energy.
(3) Commitments and Contingencies
For information concerning Puget Energy’s material contingencies and guarantees, see Note 15, Commitments and Contingencies, to the consolidated financial statements of Puget Energy.

SCHEDULE_II_VALUATION_AND_QUAL

SCHEDULE II VALUATION AND QUALIFYING ACCOUNTS AND RESERVES	12 Months Ended
	Dec. 31, 2014
Valuation and Qualifying Accounts [Abstract]
Schedule II: Valuation and Qualifying Accounts and Reserves	SCHEDULE II: VALUATION AND QUALIFYING ACCOUNTS AND RESERVES
	Puget Energy	Balance At		Additions		Deductions		Balance
	(Dollars in Thousands)	Beginning of		Charged to				At End
		Period		Costs and				Of Period
				Expenses
	Year Ended December 31, 2014
	Accounts deducted from assets on balance sheet:
	Allowance for doubtful accounts receivable	$	7,385	$	27,228	$	27,141	$	7,472
	Year Ended December 31, 2013
	Accounts deducted from assets on balance sheet:
	Allowance for doubtful accounts receivable	$	9,932	$	26,330	$	28,877	$	7,385
	Year Ended December 31, 2012
	Accounts deducted from assets on balance sheet:
	Allowance for doubtful accounts receivable	$	8,495	$	21,567	$	20,130	$	9,932
	Puget Sound Energy	Balance At		Additions		Deductions		Balance
	(Dollars in Thousands)	Beginning of		Charged to				At End
		Period		Costs and				Of Period
				Expenses
	Year Ended December 31, 2014
	Accounts deducted from assets on balance sheet:
	Allowance for doubtful accounts receivable	$	7,385	$	27,228	$	27,141	$	7,472
	Year Ended December 31, 2013
	Accounts deducted from assets on balance sheet:
	Allowance for doubtful accounts receivable	$	9,932	$	26,330	$	28,877	$	7,385
	Year Ended December 31, 2012
	Accounts deducted from assets on balance sheet:
	Allowance for doubtful accounts receivable	$	8,495	$	21,567	$	20,130	$	9,932

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation
	Puget Energy, Inc. (Puget Energy) is an energy services holding company that owns Puget Sound Energy, Inc. (PSE).  PSE is a public utility incorporated in the state of Washington that furnishes electric and natural gas services in a territory covering 6,000 square miles, primarily in the Puget Sound region.  In 2009, Puget Holdings LLC (Puget Holdings), owned by a consortium of long-term infrastructure investors, completed its merger with Puget Energy (the merger).  As a result of the merger, all of Puget Energy’s common stock is indirectly owned by Puget Holdings.  The acquisition of Puget Energy was accounted for in accordance with Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) 805, “Business Combinations” (ASC 805), as of the date of the merger.  ASC 805 requires the acquirer to recognize and measure identifiable assets acquired and liabilities assumed at fair value as of the merger date.
	The consolidated financial statements of Puget Energy reflect the accounts of Puget Energy and its subsidiary, PSE.  PSE’s consolidated financial statements include the accounts of PSE and its subsidiary.  Puget Energy and PSE are collectively referred to herein as “the Company.”  The consolidated financial statements are presented after elimination of all significant intercompany items and transactions.  PSE’s consolidated financial statements continue to be accounted for on a historical basis and PSE’s financial statements do not include any ASC 805 purchase accounting adjustments.  The preparation of financial statements in conformity with U.S. Generally Accepted Accounting Principles (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period.  Actual results could differ from those estimates.
	PSE collected Washington State excise taxes (which are a component of general retail customer rates) and municipal taxes totaling $231.7 million, $243.9 million and $244.2 million for 2014, 2013 and 2012, respectively. The Company reports the collection of such taxes on a gross basis in operation revenue and as expense in taxes other than income taxes in the accompanying consolidated statements of income.
	Beginning July 1, 2013, PSE's electric and gas operations contain a revenue decoupling mechanism under which PSE's actual energy delivery revenues related to electric transmission and distribution, gas operations and general administrative costs are compared with authorized revenues allowed under the mechanism. Any differences are deferred to a regulatory asset for under recovery or regulatory liability for over recovery. Revenues associated with power costs under the Power Cost Adjustment (PCA) mechanism and Purchased Gas Adjustment (PGA) rates are excluded from the decoupling mechanism.
Utility Plant	Utility Plant
	Puget Energy and PSE capitalize, at original cost, additions to utility plant, including renewals and betterments.  Costs include indirect costs such as engineering, supervision, certain taxes, pension and other employee benefits and an Allowance for Funds Used During Construction (AFUDC).  Replacements of minor items of property are included in maintenance expense. When the utility plant is retired and removed from service, the original cost of the property is charged to accumulated depreciation and costs associated with removal of the property, less salvage, are charged to the cost of removal regulatory liability.
	Planned Major Maintenance
	Planned major maintenance is an activity that typically occurs when PSE overhauls or substantially upgrades various systems and equipment on its natural gas fired combustion turbines on a scheduled basis. Costs related to planned major maintenance are deferred and amortized to the next scheduled major maintenance. This accounting method also follows the Washington Utilities and Transportation Commission (Washington Commission) regulatory treatment related to these generating facilities.
Depreciation and Amortization	Non-Utility Property, Plant and Equipment
	For PSE, the costs of other property, plant and equipment are stated at historical cost.  Expenditures for refurbishment and improvements that significantly add to productive capacity or extend useful life of an asset are capitalized.  Replacement of minor items are expensed on a current basis.  Gains and losses on assets sold or retired are reflected in earnings.
	Depreciation and Amortization
	For financial statement purposes, the Company provides for depreciation and amortization on a straight-line basis.  Amortization is recorded for intangibles such as regulatory assets and liabilities, computer software and franchises.  The depreciation of vehicles and equipment is allocated to the asset and expense accounts based on usage.  The annual depreciation provision stated as a percent of a depreciable electric utility plant was 2.8%, 2.8% and 2.9% in 2014, 2013 and 2012, respectively; depreciable gas utility plant was 3.4%, 3.4% and 3.4% in 2014, 2013 and 2012, respectively; and depreciable common utility plant was 8.5%, 11.4% and 11.6% in 2014, 2013 and 2012, respectively.  The decrease in depreciable common utility plant that occurred between 2014 and 2013 was primarily due to asset retirement. Depreciation on other property, plant and equipment is calculated primarily on a straight-line basis over the useful lives of the assets.  The cost of removal is collected from PSE’s customers through depreciation expense and any excess is recorded as a regulatory liability.
Goodwill	Goodwill
	In 2009, Puget Holdings completed its merger with Puget Energy.  Puget Energy remeasured the carrying amount of all its assets and liabilities to fair value, which resulted in recognition of approximately $1.7 billion in goodwill.  ASC 350, “Intangibles - Goodwill and Other” (ASC 350), requires that goodwill be tested for impairment at the reporting unit level on an annual basis and between annual tests if an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying value.  These events or circumstances could include a significant change in the Company’s business or regulatory outlook, legal factors, a sale or disposition of a significant portion of a reporting unit or significant changes in the financial markets which could influence the Company’s access to capital and interest rates.  Application of the goodwill impairment test requires judgment, including the identification of reporting units, assignment of assets and liabilities to reporting units, assignment of goodwill to reporting units and the determination of the fair value of the reporting units.  Management has determined Puget Energy has only one reporting unit.
	The goodwill recorded by Puget Energy represents the potential long-term return to the Company’s investors.  Goodwill is tested for impairment annually using a two-step process.  The first step compares the carrying amount of the reporting unit with its fair value, with a carrying value higher than fair value indicating potential impairment.  If the first step test fails, the second step is performed.  This would entail a full valuation of Puget Energy’s assets and liabilities and comparing the valuation to its carrying amounts, with the aggregate difference indicating the amount of impairment.  Goodwill of a reporting unit is required to be tested for impairment on an interim basis if an event occurs or circumstances change that would cause the fair value of a reporting unit to fall below its carrying amount.
	Puget Energy conducted its annual impairment test in 2014 using an October 1, 2014 measurement date.  The fair value of Puget Energy’s reporting unit was estimated using both discounted cash flow and market approach.  Such approaches are considered methodologies that market participants would use.  This analysis requires significant judgments, including estimation of future cash flows, which is dependent on internal forecasts, estimation of long-term rate of growth for Puget Energy business, estimation of the useful life over which cash flows will occur, the selection of utility holding companies determined to be comparable to Puget Energy and determination of an appropriate weighted-average cost of capital or discount rate.  The market approach estimates the fair value of the business based on market prices of stocks of comparable companies engaged in the same or similar lines of business.  In addition, indications of market value are estimated by deriving multiples of equity or invested capital to various measures of revenue, earnings or cash flow.  Changes in these estimates and/or assumptions could materially affect the determination of fair value and goodwill impairment of the reporting unit.  Based on the test performed, management has determined that there was no indication of impairment of Puget Energy’s goodwill as of October 1, 2014.  There were no known events or circumstances from the date of the assessment through December 31, 2014 that would impact management’s conclusion.
Cash and Cash Equivalents	Cash and Cash Equivalents
	Cash and cash equivalents consist of demand bank deposits and short-term highly liquid investments with original maturities of three months or less at the time of purchase.  The cash and cash equivalents balance at Puget Energy was $37.5 million and $44.3 million as of December 31, 2014 and 2013, respectively.  The 2014 and 2013 balance consisted of cash equivalents, which are reported at cost and approximate fair value, and were $1.8 million and $2.6 million, respectively.
Materials and Supplies	Materials and Supplies
	Materials and supplies are used primarily in the operation and maintenance of electric and natural gas distribution and transmission systems as well as spare parts for combustion turbines used for the generation of electricity.  Puget Energy and PSE record these items at weighted-average cost.
Fuel and Gas Inventory	Fuel and Gas Inventory
	Fuel and gas inventory is used in the generation of electricity and for future sales to the Company’s natural gas customers.  Fuel inventory consists of coal, diesel and natural gas used for generation.  Gas inventory consists of natural gas and Liquefied Natural Gas (LNG) held in storage for future sales.  Puget Energy and PSE record these items at the lower of cost or market value using the weighted-average cost method.
Regulatory Assets and Liabilities	Regulatory Assets and Liabilities
	PSE accounts for its regulated operations in accordance with ASC 980 “Regulated Operations” (ASC 980).  ASC 980 requires PSE to defer certain costs that would otherwise be charged to expense, if it is probable that future rates will permit recovery of such costs.  It similarly requires deferral of revenues or gains and losses that are expected to be returned to customers in the future.  Accounting under ASC 980 is appropriate as long as rates are established by or subject to approval by independent third-party regulators; rates are designed to recover the specific enterprise’s cost of service; and in view of demand for service, it is reasonable to assume that rates set at levels that will recover costs can be charged to and collected from customers.  In most cases, PSE classifies regulatory assets and liabilities as long-term due to the length of the amortization.  For further details regarding regulatory assets and liabilities, see Note 3.
Allowance for Funds Used During Construction	Allowance for Funds Used During Construction
	AFUDC represents the cost of both the debt and equity funds used to finance utility plant additions during the construction period.  The amount of AFUDC recorded in each accounting period varies depending principally upon the level of construction work in progress and the AFUDC rate used.  AFUDC is capitalized as a part of the cost of utility plant and is credited to interest expense and as a non-cash item to other income.  Cash inflow related to AFUDC does not occur until these charges are reflected in rates.
	The AFUDC rates authorized by the Washington Commission for natural gas and electric utility plant additions based on the effective dates are as follows:
	Effective Date	Washington Commission
		AFUDC Rates
	July 1, 2013 - present	7.77	%
	May 14, 2012 - June 30, 2013	7.8
	April 8, 2010 - May 13, 2012	8.1
	The Washington Commission authorized the Company to calculate AFUDC using its allowed rate of return.  To the extent amounts calculated using this rate exceed the AFUDC calculated rate using the Federal Energy Regulatory Commission (FERC) formula, PSE capitalizes the excess as a deferred asset, crediting other income.  The deferred asset is being amortized over the average useful life of PSE’s non-project electric utility plant which is approximately 30 years.
Revenue Recognition	Revenue Recognition
	Operating utility revenue is recognized when the basis of services is rendered, which includes estimated unbilled revenue, in accordance with ASC 605, “Revenue Recognition” (ASC 605).  PSE's estimate of unbilled revenue is based on a calculation using meter readings from its automated meter reading (AMR) system. The estimate calculates unbilled usage at the end of each month as the difference between the customer meter readings on the last day of the month and the last customer meter readings billed. The unbilled usage is then priced at published rates for each schedule to estimate the unbilled revenues by customer.
	The non-utility subsidiary recognizes revenue when services are performed or upon the sale of assets.  Revenue from retail sales is billed based on tariff rates approved by the Washington Commission.  Sales of Renewable Energy Credits (RECs) are deferred as a regulatory liability.
	Beginning July 1, 2013, PSE's electric and gas operations contain a revenue decoupling mechanism under which PSE's actual energy delivery revenues related to electric transmission and distribution, gas operations and general administrative costs are compared with authorized revenues allowed under the mechanism. Any differences are deferred to a regulatory asset for under recovery or regulatory liability for over recovery. Revenues associated with power costs under the PCA mechanism and PGA rates are excluded from the decoupling mechanism.
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts
	Allowance for doubtful accounts are provided for electric and natural gas customer accounts based upon a historical experience rate of write-offs of energy accounts receivable along with information on future economic outlook.  The allowance account is adjusted monthly for this experience rate.   The allowance account is maintained until either receipt of payment or the likelihood of collection is considered remote at which time the allowance account and corresponding receivable balance are written off.
	The Company’s allowance for doubtful accounts at December 31, 2014 and 2013 was $7.5 million and $7.4 million, respectively.
Self Insurance	Self-Insurance
	PSE is self-insured for storm damage and environmental contamination occurring on PSE-owned property.  In addition, PSE is required to meet a deductible for a portion of the risk associated with comprehensive liability, workers’ compensation claims and catastrophic property losses other than those which are storm related.  The Washington Commission has approved the deferral of certain uninsured qualifying storm damage costs that exceed $8.0 million which will be requested for collection in future rates.  Additionally, costs may only be deferred if the outage meets the Institute of Electrical and Electronics Engineers (IEEE) outage criteria for system average interruption duration index.
Federal Income Taxes	Federal Income Taxes
	For presentation in Puget Energy and PSE’s separate financial statements, income taxes are allocated to the subsidiaries on the basis of separate company computations of tax, modified by allocating certain consolidated group limitations which are attributed to the separate company.  Taxes payable or receivable are settled with Puget Holdings.
Natural Gas Off System Sales and Capacity Release	Natural Gas Off-System Sales and Capacity Release
	PSE contracts for firm natural gas supplies and holds firm transportation and storage capacity sufficient to meet the expected peak winter demand for natural gas by its firm customers.  Due to the variability in weather, winter peaking consumption of natural gas by most of its customers and other factors, PSE holds contractual rights to natural gas supplies and transportation and storage capacity in excess of its average annual requirements to serve firm customers on its distribution system.  For much of the year, there is excess capacity available for third-party natural gas sales, exchanges and capacity releases.  PSE sells excess natural gas supplies, enters into natural gas supply exchanges with third parties outside of its distribution area and releases to third parties excess interstate natural gas pipeline capacity and natural gas storage rights on a short-term basis to mitigate the costs of firm transportation and storage capacity for its core natural gas customers.  The proceeds from such activities, net of transactional costs, are accounted for as reductions in the cost of purchased natural gas and passed on to customers through the PGA mechanism, with no direct impact on net income.
Non-Core Gas Sales	Non-Core Gas Sales
	As part of the Company’s electric operations, PSE provides natural gas to its gas-fired generation facilities.  The projected volume of natural gas for power is relative to the price of natural gas.  Based on the market prices for natural gas, PSE may use the gas it has already purchased to generate power or PSE may sell the already purchased natural gas.  The net proceeds from selling natural gas, previously purchased for power generation, are accounted for in other electric operating revenue and are included in the PCA mechanism.
Production Tax Credit	Production Tax Credit
	Production Tax Credits (PTCs) represent federal income tax incentives available to taxpayers that generate energy from qualifying renewable sources.  PSE records the benefit of the PTCs as a regulatory liability until such time as PSE utilizes the tax credit on its tax return. Once utilized, PSE will pass the benefit to customers.
Accounting for Derivatives	Accounting for Derivatives
	ASC 815 requires that all contracts considered to be derivative instruments be recorded on the balance sheet at their fair value unless the contracts qualify for an exception.  PSE enters into derivative contracts to manage its energy resource portfolio and interest rate exposure including forward physical and financial contracts and swaps.  Some of PSE’s physical electric supply contracts qualify for the Normal Purchase Normal Sale (NPNS) exception to derivative accounting rules.  PSE may enter into financial fixed price contracts to economically hedge the variability of certain index-based contracts.  Those contracts that do not meet the NPNS exception are marked-to-market to current earnings in the statements of income, subject to deferral under ASC 980, for energy related derivatives due to the PCA mechanism and PGA mechanism.
	Puget Energy and PSE elected to de-designate all energy related derivative contracts previously recorded as cash flow hedges for the purpose of simplifying its financial reporting in 2009.  The contracts that were de-designated related to physical electric supply contracts and natural gas swap contracts used to fix the price of natural gas for electric generation.  For these contracts and for contracts initiated after such date, all mark-to-market adjustments are recognized through earnings.  The amount previously recorded in accumulated OCI is transferred to earnings in the same period or periods during which the hedged transaction affects earnings or sooner if management determines that the forecasted transaction is probable of not occurring.  As a result, the Company will continue to experience the earnings impact of these reversals from OCI in future periods. When these contracts are settled, the contract price becomes part of purchased electricity or electric generation fuel which becomes part of PSE’s PCA mechanism and the unrealized gain or loss is listed separately under energy costs, as it represents the non-rate treatment of energy costs.
	The Company may enter into swap instruments or other financial derivative instruments to manage the interest rate risk associated with its long-term debt financing and debt instruments.  As of December 31, 2014, Puget Energy has interest rate swap contracts outstanding related to its long-term debt.  For additional information, see Note 9 Accounting for Derivative Instruments and Hedging Activities.
Fair Value Measurements of Derivatives	Fair Value Measurements of Derivatives
	ASC 820, “Fair Value Measurements and Disclosures” (ASC 820), defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price).  As permitted under ASC 820, the Company utilizes a mid-market pricing convention (the mid-point price between bid and ask prices) as a practical expedient for valuing the majority of its assets and liabilities measured and reported at fair value.  The Company utilizes market data or assumptions that market participants would use in pricing the asset or liability, including assumptions about risk and the risks inherent in the inputs to the valuation technique.  These inputs can be readily observable, market corroborated or generally unobservable.  The Company primarily applies the market approach for recurring fair value measurements as it believes that the approach is used by market participants for these types of assets and liabilities.  Accordingly, the Company utilizes valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs.
	The Company values derivative instruments based on daily quoted prices from an independent external pricing service.  When external quoted market prices are not available for derivative contracts, the Company uses a valuation model that uses volatility assumptions relating to future energy prices based on specific energy markets and utilizes externally available forward market price curves.  All derivative instruments are sensitive to market price fluctuations that can occur on a daily basis.  For additional information, see Note 10 Fair Value Measurements.
Debt Related Costs	Debt Related Costs
	Debt premiums, discounts, expenses and amounts received or incurred to settle hedges are amortized over the life of the related debt for the Company.  The premiums and costs associated with reacquired debt are deferred and amortized over the life of the related new issuance, in accordance with ratemaking treatment for PSE.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2014
Entity Information [Line Items]
Schedule of Authorized AFUDC Rates	The AFUDC rates authorized by the Washington Commission for natural gas and electric utility plant additions based on the effective dates are as follows:
	Effective Date	Washington Commission
		AFUDC Rates
	July 1, 2013 - present	7.77	%
	May 14, 2012 - June 30, 2013	7.8
	April 8, 2010 - May 13, 2012	8.1
Schedule of Accumulated Other Comprehensive Income (Loss)	The following tables set forth the components of the Company’s accumulated other comprehensive income (loss) at:
	Puget Energy	December 31,
	(Dollars in Thousands)	2014			2013
	Net unrealized loss on energy derivative instruments	$	(333	)	$	(705	)
	Net unrealized loss on interest rate swaps	—			(94		)
	Net unrealized loss and prior service cost on pension plans	(36,710		)	48,514
	Total Puget Energy, net of tax	$	(37,043	)	$	47,715
	Puget Sound Energy	December 31,
	(Dollars in Thousands)	2014			2013
	Net unrealized loss on energy derivative instruments	$	(686	)	$	(2,027	)
	Net unrealized loss on treasury interest rate swaps	(5,990		)	(6,307		)
	Net unrealized loss and prior service cost on pension plans	(164,281		)	(87,405		)
	Total PSE, net of tax	$	(170,957	)	$	(95,739	)
	The following tables present the changes in the Company’s accumulated other comprehensive income (loss) (AOCI) by component for the years ended December 31, 2014, 2013 and 2012, respectively.
	Puget Energy	Net unrealized gain (loss) and prior service cost on pension plans			Net unrealized gain (loss) on energy derivative instruments			Net unrealized gain (loss) on interest rate swaps
	Changes in AOCI, net of tax
	(Dollars in Thousands)										Total
	Balance at December 31, 2011	$	(15,195	)	$	(1,113	)	$	(14,599	)	$	(30,907	)
	Other comprehensive income (loss) before reclassifications	(13,574		)	—			—			(13,574		)
	Amounts reclassified from accumulated other comprehensive income (loss), net of tax	(296		)	371			11,577			11,652
	Net current-period other comprehensive income (loss)	(13,870		)	371			11,577			(1,922		)
	Balance at December 31, 2012	$	(29,065	)	$	(742	)	$	(3,022	)	$	(32,829	)
	Other comprehensive income (loss) before reclassifications	76,004			—			—			76,004
	Amounts reclassified from accumulated other comprehensive income (loss), net of tax	1,575			37			2,928			4,540
	Net current-period other comprehensive income (loss)	77,579			37			2,928			80,544
	Balance at December 31, 2013	$	48,514		$	(705	)	$	(94	)	$	47,715
	Other comprehensive income (loss) before reclassifications	(84,301		)	—			—			(84,301		)
	Amounts reclassified from accumulated other comprehensive income (loss), net of tax	(923		)	372			94			(457		)
	Net current-period other comprehensive income (loss)	(85,224		)	372			94			(84,758		)
	Balance at December 31, 2014	$	(36,710	)	$	(333	)	$	—		$	(37,043	)
	Puget Sound Energy	Net unrealized gain (loss) and prior service cost on pension plans			Net unrealized gain (loss) on energy derivative instruments			Net unrealized gain (loss) on treasury interest rate swaps
	Changes in AOCI, net of tax
	(Dollars in Thousands)										Total
	Balance at December 31, 2011	$	(168,704	)	$	(12,934	)	$	(6,941	)	$	(188,579	)
	Other comprehensive income (loss) before reclassifications	(17,049		)	—			—			(17,049		)
	Amounts reclassified from accumulated other comprehensive income (loss), net of tax	9,755			8,358			317			18,430
	Net current-period other comprehensive income (loss)	(7,294		)	8,358			317			1,381
	Balance at December 31, 2012	$	(175,998	)	$	(4,576	)	$	(6,624	)	$	(187,198	)
	Other comprehensive income (loss) before reclassifications	74,969			—			—			74,969
	Amounts reclassified from accumulated other comprehensive income (loss), net of tax	13,624			2,549			317			16,490
	Net current-period other comprehensive income (loss)	88,593			2,549			317			91,459
	Balance at December 31, 2013	$	(87,405	)	$	(2,027	)	$	(6,307	)	$	(95,739	)
	Other comprehensive income (loss) before reclassifications	(84,955		)	—			—			(84,955		)
	Amounts reclassified from accumulated other comprehensive income (loss), net of tax	8,079			1,341			317			9,737
	Net current-period other comprehensive income (loss)	(76,876		)	1,341			317			(75,218		)
	Balance at December 31, 2014	$	(164,281	)	$	(686	)	$	(5,990	)	$	(170,957	)

Regulation_and_Rates_Tables

Regulation and Rates (Tables)	12 Months Ended
	Dec. 31, 2014
Regulation and Rates [Line Items]
Schedule of Allowed Return on the Net Regulatory Assets and Liabilities	Below is a chart with the allowed return on the net regulatory assets and liabilities and the associated time periods:
	Period	Rate of Return	After-Tax Return
	July 1, 2013 - present	7.77%	6.69%
	May 14, 2012 - June 30, 2013	7.8	6.71
	April 8, 2010 - May 13, 2012	8.1	6.9
Schedule of Net Regulatory Assets and Liabilities	The net regulatory assets and liabilities at December 31, 2014 and 2013 included the following:
	Puget Sound Energy	Remaining Amortization Period	December 31,
	(Dollars in Thousands)		2014			2013
	PGA deferral of unrealized losses on derivative instruments	(a)	$	69,280		$	27,555
	Chelan PUD contract initiation	16.8 Years	119,316			126,404
	Storm damage costs electric	1 to 4 years	118,824			116,328
	Environmental remediation	(a)	66,018			57,342
	Baker Dam licensing operating and maintenance costs	44 years	61,577			57,270
	Snoqualmie licensing operating and maintenance costs	30 years	9,202			10,881
	Colstrip common property	9.5 years	6,764			7,479
	Deferred income taxes	(a)	94,913			146,350
	Deferred Washington Commission AFUDC	35 years	53,709			55,495
	Energy conservation costs	1 to 2 years	42,374			35,987
	Unamortized loss on reacquired debt	1 to 21.5 years	35,667			37,832
	White River relicensing and other costs	17.9 years	26,685			28,190
	Mint Farm ownership and operating costs	10.3 years	20,320			22,320
	Investment in Bonneville Exchange power contract	2.5 years	8,816			12,343
	Ferndale	4.8 years	19,232			22,811
	Lower Snake River	1.3 to 22.3 years	86,275			92,924
	Snoqualmie	3.8 years	6,798			8,009
	Property tax tracker	Less than 2 years	32,253			22,134
	PGA receivable	1 year	21,073			—
	PCA mechanism	(a)	4,623			—
	Electron unrecovered loss	4 years	14,008			—
	Decoupling under-collection	Less than 2 years	55,363			—
	Various other regulatory assets	Varies	14,312			8,078
	Total PSE regulatory assets		$	987,402		$	895,732
	Cost of removal	(b)	$	(313,088	)	$	(269,536	)
	Production tax credits	(c)	(93,616		)	(93,618		)
	PGA payable	1 year	—			(5,938		)
	PCA mechanism	(a)	—			(5,345		)
	Decoupling over-collection	Less than 2 years	(12,582		)	(20,535		)
	Summit purchase option buy-out	5.8 years	(9,188		)	(10,763		)
	Deferred gain on Jefferson County sale	Less than 1 year	(4,731		)	(60,844		)
	Deferred credit on Biogas sale	1 year	(1,445		)	(10,908		)
	Deferred credit on gas pipeline capacity	Varies up to 3.8 years	(3,564		)	(4,508		)
	Renewable energy credits	1 year	(2,383		)	(5,820		)
	Treasury grants	5 to 44 years	(180,496		)	(203,889		)
	Deferral of treasury grant amortization	Less than 4 years	(8,197		)	—
	Various other regulatory liabilities	Up to 4 years	(6,092		)	(5,755		)
	Total PSE regulatory liabilities		$	(635,382	)	$	(697,459	)
	PSE net regulatory assets (liabilities)		$	352,020		$	198,273
	_______________
	(a)	Amortization periods vary depending on timing of underlying transactions or awaiting regulatory approval in a future Washington Commission rate proceeding.
	(b)	The balance is dependent upon the cost of removal of underlying assets and the life of utility plant.
	(c)	Amortization will begin once PTCs are utilized by PSE on its tax return.
	Puget Energy	Remaining Amortization Period	December 31,
	(Dollars in Thousands)		2014			2013
	Total PSE regulatory assets	(a)	$	987,402		$	895,732
	Puget Energy acquisition adjustments:
	Regulatory assets related to power contracts	1 to 22 years	29,816			33,753
	Various other regulatory assets	Varies	561			517
	Total Puget Energy regulatory assets		$	1,017,779		$	930,002
	Total PSE regulatory liabilities	(a)	$	(635,382	)	$	(697,459	)
	Puget Energy acquisition adjustments:
	Regulatory liabilities related to power contracts	1 to 37 years	(391,389		)	(443,065		)
	Various other regulatory liabilities	Varies	(2,820		)	(2,884		)
	Total Puget Energy regulatory liabilities		$	(1,029,591	)	$	(1,143,408	)
	Puget Energy net regulatory asset (liabilities)		$	(11,812	)	$	(213,406	)
	_______________
	(a)	Puget Energy’s regulatory assets and liabilities include purchase accounting adjustments under ASC 805 as a result of the merger.
Schedule of Graduated Scale of Rate Adjustment Mechanisms	The graduated scale is as follows:
	Annual Power Cost Variability	Customers’ Share	Company’s Share
	+/- $20 million	0%	100%
	+/- $20 million - $40 million	50%	50%
	+/- $40 million - $120 million	90%	10%
	+/- $120 + million	95%	5%
Electric
Regulation and Rates [Line Items]
Schedule of Effects on Annual Revenue Due to Approved Rate Adjustments	The following table sets forth electric rate adjustments approved by the Washington Commission and the corresponding impact on PSE’s revenue based on the effective dates:
	Type of Rate	Effective Date	Average	Increase (Decrease)
	Adjustment		Percentage	in Revenue
			Increase (Decrease)	(Dollars in Millions)
			in Rates
	PCORC	1-Dec-14	-0.90%	($19.40)
	Conservation Rider	1-May-14	0.50%	12.2
	Decoupling Rate Filing	1-May-14	0.5	10.6
	Property Tax Tracker	1-May-14	0.5	11
	PCORC	1-Nov-13	0.5	10.5
	Decoupling Rate Filing	1-Jul-13	1	21.4
	Expedited Rate Filing	1-Jul-13	1.5	30.7
	Electric General Rate Case	14-May-12	3.2	63.3
Gas
Regulation and Rates [Line Items]
Schedule of Effects on Annual Revenue Due to Approved Rate Adjustments	The following table sets forth natural gas rate adjustments that were approved by the Washington Commission and the corresponding impact to PSE’s annual revenue based on the effective dates:
	Type of Rate	Effective Date	Average	Annual
	Adjustment		Percentage	Increase (Decrease)
			Increase (Decrease)	in Revenue
			in Rates	(Dollars in Millions)
	Purchased Gas Adjustment	1-Nov-14	-2.50%	($23.30)
	Decoupling Rate Filing	1-May-14	-0.1	-1
	Purchased Gas Adjustment	1-Nov-13	0.4	4
	Decoupling Rate Filing	1-Jul-13	1.1	10.8
	Expedited Rate Filing	1-Jul-13	-0.2	-2
	Purchased Gas Adjustment	1-Nov-12	-7.7	-77
	Natural Gas General Rate Case	14-May-12	1.3	13.4
	Purchased Gas Adjustment	1-Nov-11	-4.3	-43.5
	Natural Gas General Tariff Adjustment	1-Apr-11	1.8	19

Utility_Plant_Tables

Utility Plant (Tables)	12 Months Ended
	Dec. 31, 2014
Utility Plant [Abstract]
Schedule of Utility Plant
			Puget Energy						Puget Sound Energy
	Utility Plant	Estimated	At December 31,						At December 31,
		Useful Life
	(Dollars In Thousands)	(Years)	2014			2013			2014			2013
	Electric, gas and common utility plant classified by prescribed accounts :
	Distribution plant	Oct-50	$	4,748,988		$	4,448,451		$	6,417,551		$	6,127,732
	Production plant	25-125	2,973,853			2,966,223			3,907,224			3,948,270
	Transmission plant	45-65	1,189,296			1,043,605			1,306,009			1,162,929
	General plant	May-35	481,116			504,965			553,130			599,156
	Intangible plant (including capitalized software)	Mar-50	311,959			316,614			304,135			309,972
	Plant acquisition adjustment	30-Jul	242,826			242,826			282,792			282,792
	Underground storage	25-60	28,859			27,857			42,494			41,501
	Liquefied natural gas storage	25-45	12,628			12,622			14,498			14,492
	Plant held for future use	NA	54,996			28,742			55,148			28,895
	Recoverable Cushion Gas	NA	8,655			8,655			8,655			8,655
	Plant not classified	1-100	91,519			124,589			91,519			124,589
	Grant	NA	(105,659		)	—			(105,659		)	—
	Capital leases, net of accumulated amortization 1	5	9,473			17,051			9,473			17,051
	Less: accumulated provision for depreciation		(1,611,220		)	(1,373,178		)	(4,449,680		)	(4,297,012		)
	Subtotal		$	8,437,289		$	8,369,022		$	8,437,289		$	8,369,022
	Construction work in progress	NA	239,690			310,318			239,690			310,318
	Net utility plant		$	8,676,979		$	8,679,340		$	8,676,979		$	8,679,340
	_______________
	1	Accumulated amortization of capital leases at Puget Energy was $28.4 million in 2014 and $20.8 million in 2013.  Accumulated amortization of capital leases at PSE was $28.4 million in 2014 and $20.8 million in 2013.
Schedule of Jointly Owned Utility Plants	These amounts are also included in the Utility Plant table above.
					Puget Energy’s						Puget Sound Energy’s
					Share						Share
	Jointly Owned Generating Plants	Energy Source (Fuel)	Company’s Ownership Share		Plant in Service at Cost			Accumulated Depreciation			Plant in Service at Cost			Accumulated Depreciation
	(Dollars in Thousands)
	Colstrip Units 1 & 2	Coal	50	%	$	158,516		$	(12,047	)	$	293,103		$	(146,635	)
	Colstrip Units 3 & 4	Coal	25	%	234,787			(28,763		)	509,619			(303,594		)
	Colstrip Units 1 – 4 Common Facilities 1	Coal	various		83			(21		)	252			(189		)
	Frederickson 1	Gas	49.85	%	61,771			(5,750		)	70,719			(14,698		)
	Jackson Prairie	Gas Storage	33.34	%	28,185			(4,099		)	42,494			(18,409		)
Schedule of Asset Retirement Obligations	The following table describes all changes to the Company’s ARO liability:
		At December 31,
	(Dollars in Thousands)	2014			2013
	Asset retirement obligation at beginning of period	$	48,687		$	45,496
	New asset retirement obligation recognized in the period	—			350
	Liability settled in the period	(602		)	(1,188		)
	Revisions in estimated cash flows	(480		)	2,769
	Accretion expense	1,304			1,260
	Asset retirement obligation at end of period	$	48,909		$	48,687

LongTerm_Debt_Tables

Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2014
Debt Instrument [Line Items]
Schedule of Long-Term Debt Instruments
	(Dollars in Thousands)			At December 31,
	Series	Type	Due	2014			2013
	Puget Sound Energy:
	7.35%	First Mortgage Bond	2015	$	10,000		$	10,000
	7.36%	First Mortgage Bond	2015	2,000			2,000
	5.20%	Senior Secured Note	2015	150,000			150,000
	6.75%	Senior Secured Note	2016	250,000			250,000
	5.50%	Promissory Note 1	2017	2,412			2,412
	6.74%	Senior Secured Note	2018	200,000			200,000
	7.15%	First Mortgage Bond	2025	15,000			15,000
	7.20%	First Mortgage Bond	2025	2,000			2,000
	7.02%	Senior Secured Note	2027	300,000			300,000
	7.00%	Senior Secured Note	2029	100,000			100,000
	3.90%	Pollution Control Bond	2031	138,460			138,460
	4.00%	Pollution Control Bond	2031	23,400			23,400
	5.48%	Senior Secured Note	2035	250,000			250,000
	6.72%	Senior Secured Note	2036	250,000			250,000
	6.27%	Senior Secured Note	2037	300,000			300,000
	5.76%	Senior Secured Note	2039	350,000			350,000
	5.80%	Senior Secured Note	2040	325,000			325,000
	5.76%	Senior Secured Note	2040	250,000			250,000
	4.43%	Senior Secured Note	2041	250,000			250,000
	5.64%	Senior Secured Note	2041	300,000			300,000
	4.70%	Senior Secured Note	2051	45,000			45,000
	6.97%	Junior Subordinated Note	2067	250,000			250,000
		Unamortized discount on senior notes		(13		)	(14		)
	PSE long-term debt			$	3,763,259		$	3,763,258
	Puget Energy:
		Fair value adjustment of PSE long-term debt		$	(218,619	)	$	(229,746	)
		Credit Facility	2017	—			299,000
		Term-Loan	2016	100,000			—
		Term-Loan	2017	100,000			—
		Term-Loan	2016	99,000			—
	6.50%	Senior Secured Note	2020	450,000			450,000
	6.00%	Senior Secured Note	2021	500,000			500,000
	5.63%	Senior Secured Note	2022	450,000			450,000
		Unamortized discount on senior notes		(32		)	(36		)
	Total Puget Energy long-term debt			$	5,243,608		$	5,232,476
	____________
	1	Puget Western, Inc., a wholly owned subsidiary of PSE, Promissory Note.
Schedule of Maturities of Long-Term Debt	The principal amounts of long-term debt maturities for the next five years and thereafter are as follows:
	(Dollars in Thousands)	2015			2016			2017		2018		2019		Thereafter		Total
	Maturities of:
	PSE long-term debt	$	162,000		$	250,000		$	2,412	$	200,000	$	—	$	3,148,860	$	3,763,272
	Puget Energy long-term debt	—			199,000			100,000		—		—		1,400,000		1,699,000
	Puget Energy long-term debt	$	162,000		$	449,000		$	102,412	$	200,000	$	—	$	4,548,860	$	5,462,272

Leases_Tables

Leases (Tables)	12 Months Ended
	Dec. 31, 2014
Leases [Abstract]
Schedule of Operating Lease Expense	Operating lease expenses net of sublease receipts were:
	(Dollars in Thousands)
	At December 31,
	2014	$	30,737
	2013	29,392
	2012	29,661
Schedule of Future Minimum Lease Payments for Non-cancellable Leases	Future minimum lease payments for non-cancelable leases net of sublease receipts are:
	(Dollars in Thousands)
	At December 31,	Operating		Capital
	2015	$	17,677	$	8,160
	2016	21,454		2,178
	2017	22,179		—
	2018	20,423		—
	2019	15,180		—
	Thereafter	120,791		—
	Total minimum lease payments	$	217,704	$	10,338

Accounting_for_Derivative_Inst1

Accounting for Derivative Instruments and Hedging Activities (Tables)	12 Months Ended
	Dec. 31, 2014
Derivative [Line Items]
Schedule of Credit Risk Related Contingent Features [Table Text Block]	The table below presents the fair value of the overall contractual contingent liability positions for the Company's derivative activity at December 31, 2014:
	Puget Energy and Puget Sound Energy	Fair Value 1			Posted			Contingent
	Contingent Feature	Liability			Collateral			Collateral
	(Dollars in Thousands)
	Credit rating 2	$	(37,398	)	$	—		$	37,398
	Requested credit for adequate assurance	(66,468		)	—			—
	Forward value of contract 3	(2,490		)	—			—
	Total	$	(106,356	)	$	—		$	37,398
	__________
	1	Represents the derivative fair value of contracts with contingent features for counterparties in net derivative liability positions. Excludes NPNS, accounts payable and accounts receivable.
	2	Failure by PSE to maintain an investment grade credit rating from each of the major credit rating agencies provides counterparties a contractual right to demand collateral.
	3	Collateral requirements may vary, based on changes in the forward value of underlying transactions relative to contractually defined collateral thresholds.
Offsetting Assets and Liabilities [Table Text Block]	The following tables present the potential effect of netting arrangements, including rights of set-off associated with the Company's derivative assets and liabilities:
	Puget Energy and Puget Sound Energy
	At December 31, 2014
	(Dollars in Thousands)	Gross Amounts Recognized in the Statement of Financial Position 1			Gross Amounts Offset in the Statement of Financial Position			Net of Amounts Presented in the Statement of Financial Position			Gross Amounts Not Offset in the Statement of Financial Position
											Commodity Contracts			Cash Collateral Received/Posted			Net Amount
	Assets
	Energy Derivative Contracts	$	24,348		$	—		$	24,348		$	(23,066	)	$	—		$	1,282
	Liabilities
	Energy Derivative Contracts	$	196,035		$	—		$	196,035		$	(23,066	)	$	(20	)	$	172,949
	Interest Rate Swaps 2	$	9,073		$	—		$	9,073		$	—		$	—		$	9,073
	Puget Energy and Puget Sound Energy
	At December 31, 2013
	(Dollars in Thousands)	Gross Amounts Recognized in the Statement of Financial Position 1			Gross Amounts Offset in the Statement of Financial Position			Net of Amounts Presented in the Statement of Financial Position			Gross Amounts Not Offset in the Statement of Financial Position
											Commodity Contracts			Cash Collateral Received/Posted			Net Amount
	Assets
	Energy Derivative Contracts	$	26,600		$	—		$	26,600		$	(19,491	)	$	—		$	7,109
	Liabilities
	Energy Derivative Contracts	$	72,988		$	—		$	72,988		$	(19,491	)	$	—		$	53,497
	Interest Rate Swaps 2	$	13,223		$	—		$	13,223		$	—		$	—		$	13,223
	___________
	1.	All Derivative Contract deals are executed under ISDA, NAESB and WSPP Master Netting Agreements with Right of Offset.
	2	Interest Rate Swap Contracts are only held at Puget Energy.
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value	The following table presents the volumes, fair values and locations of the Company's derivative instruments recorded on the balance sheets:
	Puget Energy and	Year Ended December 31,
	Puget Sound Energy
	(Dollars in Thousands)	Volumes (millions)				Assets 1						Liabilities 2
		2014		2013		2014			2013			2014			2013
	Interest rate swap derivatives 3	$450.00		$450.00		$	—		$	—		$	9,073		$	13,223
	Electric portfolio derivatives	*		*		4,822			18,479			107,228			37,312
	Natural gas derivatives (MMBtus) 4	360.4		423.5		19,526			8,121			88,807			35,676
	Total derivative contracts					$	24,348		$	26,600		$	205,108		$	86,211
	Current					$	21,178		$	18,867		$	142,195		$	48,049
	Long-term					3,170			7,733			62,913			38,162
	Total derivative contracts					$	24,348		$	26,600		$	205,108		$	86,211
	___________
	1	Balance sheet location: Current and Long-term Unrealized gain on derivative instruments.
	2	Balance sheet location: Current and Long-term Unrealized loss on derivative instruments.
	3	Interest rate swap contracts are only held at Puget Energy.
	4	PSE had a net derivative liability and an offsetting regulatory asset of $69.3 million at December 31, 2014 and $27.6 million at December 31, 2013 related to contracts used to economically hedge the cost of physical gas purchased to serve natural gas customers. All fair value adjustments on derivatives relating to the natural gas business have been deferred in accordance with ASC 980, due to the PGA mechanism.
	*	Electric portfolio derivatives consist of electric generation fuel of 140.2 million One Million British Thermal Units (MMBtus) and purchased electricity of 5.4 million Megawatt Hours (MWhs) at December 31, 2014 and 145.6 million MMBtus and 8.6 million MWhs at December 31, 2013.
Parent Company [Member]
Derivative [Line Items]
Schedule of Derivative Instruments, Effect on Other Comprehensive Income (Loss) [Table Text Block]	The following tables present the Company's pre-tax gain (loss) on derivatives that were previously in a cash flow hedge relationship, and subsequently reclassified out of accumulated OCI into income:
	Puget Energy		Year Ended December 31,
	(Dollars in Thousands)	Location	2014			2013			2012
	Interest rate contracts:	Interest expense	$	(144	)	$	(4,505	)	$	(17,811	)
	Commodity contracts:
	Electric derivatives	Electric generation fuel	—			—			100
		Purchased electricity	(572		)	(57		)	(671		)
	Total		$	(716	)	$	(4,562	)	$	(18,382	)
Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance [Table Text Block]	The following tables present the effect and locations of the Company's derivatives not designated as hedging instruments, recorded on the statements of income:
	Puget Energy		Year Ended December 31,
	(Dollars in Thousands)	Location	2014			2013			2012
	Interest rate contracts:	Other deductions	$	(3,915	)	$	2,420		$	(4,288	)
		Interest expense	500			(5,904		)	(29,727		)
	Commodity contracts:
	Electric derivatives	Unrealized gain (loss) on derivative instruments, net 1	(84,146		)	102,744			131,407
		Electric generation fuel	6,511			(27,008		)	(66,762		)
		Purchased electricity	(4,212		)	(38,299		)	(138,551		)
	Total gain (loss) recognized in income on derivatives		$	(85,262	)	$	33,953		$	(107,921	)
	___________
	1	For 2012, the amount differs from the amount stated in the statement of income as it does not include amortization related to contracts that were recorded at fair value at the time of the February 2009 merger and subsequently designated as NPNS of $2.2 million for the year ended December 31, 2012.
PUGET SOUND ENERGY, INC.
Derivative [Line Items]
Schedule of Derivative Instruments, Effect on Other Comprehensive Income (Loss) [Table Text Block]
	Puget Sound Energy		Year Ended December 31,
	(Dollars in Thousands)	Location	2014			2013			2012
	Interest rate contracts:	Interest expense	$	(488	)	$	(488	)	$	(488	)
	Commodity contracts:
	Electric derivatives	Electric generation fuel	—			—			97
		Purchased electricity	(2,063		)	(3,922		)	(12,955		)
	Total		$	(2,551	)	$	(4,410	)	$	(13,346	)
Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance [Table Text Block]
	Puget Sound Energy		Year Ended December 31,
	(Dollars in Thousands)	Location	2014			2013			2012
	Commodity contracts:
	Electric derivatives	Unrealized gain (loss) on derivative instruments, net	$	(85,636	)	$	98,880		$	119,120
		Electric generation fuel	6,511			(27,008		)	(66,762		)
		Purchased electricity	(4,212		)	(38,299		)	(138,551		)
	Total gain (loss) recognized in income on derivatives		$	(83,337	)	$	33,573		$	(86,193	)

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The following table presents the carrying value for cash, cash equivalents, restricted cash, notes receivable and short-term debt by level, within the fair value hierarchy. The carrying values below are representative of fair values due to the short-term nature of these financial instruments.
	Puget Energy	Carrying / Fair Value									Carrying / Fair Value
		At December 31, 2014									At December 31, 2013
	(Dollars in Thousands)	Level 1			Level 2			Total			Level 1			Level 2			Total
	Assets:
	Cash and Cash Equivalents	$	37,527		$	—		$	37,527		$	44,302		$	—		$	44,302
	Restricted Cash	32,863			—			32,863			7,171			—			7,171
	Notes Receivable and Other	—			53,503			53,503			—			53,449			53,449
	Total assets	$	70,390		$	53,503		$	123,893		$	51,473		$	53,449		$	104,922
	Liabilities:
	Short-term debt	$	85,000		$	—		$	85,000		$	162,000		$	—		$	162,000
	Total liabilities	$	85,000		$	—		$	85,000		$	162,000		$	—		$	162,000
Fair Value Inputs, Liabilities, Quantitative Information	The fair value of the junior subordinated and long-term notes were estimated using the discounted cash flow method with U.S. Treasury yields and Company credit spreads as inputs, interpolating to the maturity date of each issue. Carrying values and estimated fair values were as follows:
	Puget Energy		December 31, 2014						December 31, 2013
	(Dollars in Thousands)	Level	Carrying			Fair			Carrying			Fair
			Value			Value			Value			Value
	Liabilities:
	Junior subordinated notes	2	$	250,000		$	276,235		$	250,000		$	269,366
	Long-term debt (fixed-rate), net of discount	2	4,694,608			6,083,554			4,683,476			5,594,314
	Long-term debt (variable-rate)	2	299,000			299,000			299,000			299,000
	Total		$	5,243,608		$	6,658,789		$	5,232,476		$	6,162,680
	Puget Sound Energy		December 31, 2014						December 31, 2013
	(Dollars in Thousands)	Level	Carrying			Fair			Carrying			Fair
			Value			Value			Value			Value
	Liabilities:
	Junior subordinated notes	2	$	250,000		$	276,235		$	250,000		$	269,366
	Long-term debt (fixed-rate), net of discount	2	3,513,259			4,437,473			3,513,258			4,038,455
	Total		$	3,763,259		$	4,713,708		$	3,763,258		$	4,307,821
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]
	Puget Energy and	Year Ended December 31,
	Puget Sound Energy
	Level 3 Roll-Forward Net (Liability)	2014									2013									2012
	(Dollars in Thousands)	Electric			Gas			Total			Electric			Gas			Total			Electric			Gas			Total
	Balance at beginning of period	$	(15,421	)	$	(361	)	$	(15,782	)	$	(33,924	)	$	(1,602	)	$	(35,526	)	$	(90,311	)	$	(5,041	)	$	(95,352	)
	Changes during period
	Realized and unrealized energy derivatives:
	Included in earnings 1	(5,537		)	—			(5,537		)	(10,491		)	—			(10,491		)	(21,362		)	—			(21,362		)
	Included in regulatory assets / liabilities	—			1,630			1,630			—			(945		)	(945		)	—			(1,937		)	(1,937		)
	Settlements 2	1,036			(1,534		)	(498		)	11,609			(754		)	10,855			59,133			969			60,102
	Transferred into Level 3	5,155			(585		)	4,570			(7,799		)	—			(7,799		)	(55,548		)	(297		)	(55,845		)
	Transferred out of Level 3	2,705			(1,190		)	1,515			25,184			2,940			28,124			74,164			4,704			78,868
	Balance at end of period	$	(12,062	)	$	(2,040	)	$	(14,102	)	$	(15,421	)	$	(361	)	$	(15,782	)	$	(33,924	)	$	(1,602	)	$	(35,526	)
	_______________
	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 $(9.6) million, $(13.4) million, and $(15.2) million for the years ended December 31, 2014, 2013 and 2012, respectively.
	2	The Company had no purchases, sales or issuances during the reported periods.
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Table Text Block]	At December 31, 2014, Puget Energy completed a valuation and impairment test of its purchased power contracts classified as intangible assets. The valuation indicated a fair value of $437.6 million with an impairment to the Wells hydro contract. As of December 31, 2014, the carrying value for this contract was $65.3 million and its fair value on a discounted basis was $62.1 million, thereby requiring a write-down of $3.2 million to this intangible asset with a corresponding reduction in the regulatory liability.
	Below are significant unobservable inputs used in estimating the impaired long term power purchase contract's fair value on December 31, 2014:
	Valuation Technique	Unobservable Input	Low	High	Average
	Discounted cash flow	Power prices	$19.30 per MWh	$37.06 per MWh	$29.53 per MWh
	Discounted cash flow	Power contract costs (in thousands)	$3,015 per qtr	$4,783 per qtr	$4,469 per qtr
	At June 30, 2013, Puget Energy completed a valuation and impairment test of its purchased power contracts classified as intangible assets. The valuation indicated a fair value of $484.1 million with an impairment to the Priest Rapids Reasonable Portion intangible asset contract. As of June 30, 2013, the carrying value for this intangible asset contract was $47.1 million and its fair value on a discounted basis was determined to be an asset of $33.6 million, thereby requiring a write-down of $13.5 million to the intangible asset with a corresponding reduction in the regulatory liability.
	Below are significant unobservable inputs used in estimating the impaired long term power purchase contract's fair value on June 30, 2013:
	Valuation Technique	Unobservable Input	Low	High	Average
	Discounted cash flow	Power prices	$30.85 per MWh	$65.35 per MWh	$48.47 per MWh
	Discounted cash flow	Power contract costs (in thousands)	$389 per yr	$6,845 per yr	$4,110 per yr
	The valuations were measured using the income approach. Significant inputs included forward electricity prices and power contract pricing which provided future net cash flow estimates which are classified as Level 3 within the fair value hierarchy. A less significant input is the discount rate reflective of PSE's cost of capital used in the valuation.
	Below are the forward price ranges for the Company's commodity contracts, as of December 31, 2014:
	(Dollars in Thousands)
		Fair Value				Range
	Derivative Instrument	Assets 1	Liabilities 1	Valuation Technique	Unobservable Input	Low	High	Weighted Average
	Electric	$3,168	$15,230	Discounted cash flow	Power Prices	$21.79 per MWh	$35.46 per MWh	$32.89 per MWh
	Natural gas	$1,462	$3,502	Discounted cash flow	Natural Gas Prices	$3.11 per MMBtu	$3.83 per MMBtu	$3.28 per MMBtu
	_______________
	1	The valuation techniques, unobservable inputs and ranges are the same for asset and liability positions.
	The significant unobservable inputs listed above would have a direct impact on the fair values of the above instruments if they were adjusted. Consequently significant increases or decreases in the forward prices of electricity or natural gas in isolation would result in a significantly higher or lower fair value for Level 3 assets and liabilities. Generally, interrelationships exist between market prices of natural gas and power. As such, an increase in natural gas pricing would potentially have a similar impact on forward power markets. At December 31, 2014, a hypothetical 10% increase or decrease in market prices of natural gas and electricity would change the fair value of the Company's derivative portfolio, classified as Level 3 within the fair value hierarchy, by $3.9 million.
	Long-Lived Assets Measured at Fair Value on a Nonrecurring Basis
	At the time of merger, Puget Energy recorded the fair value of its intangible assets in accordance with ASC 360, “Property, Plant, and Equipment,” (ASC 360). The fair value assigned to the power contracts was determined using an income approach comparing the contract rate to the market rate for power over the remaining period of the contracts incorporating non-performance risk. Management also incorporated certain assumptions related to quantities and market presentation that it believes market participants would make in the valuation. The fair value of the power contracts is amortized as the contracts settle.
	ASC 360 requires long-lived assets to be tested for impairment on an annual basis, and upon the occurrence of any events or circumstances that would be more likely than not to reduce the fair value of the long-lived assets below their carrying value. One such triggering event is a significant decrease in the forward market prices of power.
	At December 31, 2014, Puget Energy completed a valuation and impairment test of its purchased power contracts classified as intangible assets. The valuation indicated a fair value of $437.6 million with an impairment to the Wells hydro contract. As of December 31, 2014, the carrying value for this contract was $65.3 million and its fair value on a discounted basis was $62.1 million, thereby requiring a write-down of $3.2 million to this intangible asset with a corresponding reduction in the regulatory liability.
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The following tables present the Company's financial assets and liabilities by level, within the fair value hierarchy, that were accounted for at fair value on a recurring basis and the reconciliation of the changes in the fair value of Level 3 derivatives in the fair value hierarchy:
	Puget Energy	Fair Value									Fair Value
		At December 31, 2014									At December 31, 2013
	(Dollars in Thousands)	Level 2			Level 3			Total			Level 2			Level 3			Total
	Interest rate derivative instruments	$	9,073		$	—		$	9,073		$	13,223		$	—		$	13,223
	Total derivative liabilities	$	9,073		$	—		$	9,073		$	13,223		$	—		$	13,223
	Puget Energy and	Fair Value									Fair Value
	Puget Sound Energy	At December 31, 2014									At December 31, 2013
	(Dollars in Thousands)	Level 2			Level 3			Total			Level 2			Level 3			Total
	Assets:
	Electric derivative instruments	$	1,654		$	3,168		$	4,822		$	14,661		$	3,818		$	18,479
	Natural gas derivative instruments	18,064			1,462			19,526			5,448			2,673			8,121
	Total assets	$	19,718		$	4,630		$	24,348		$	20,109		$	6,491		$	26,600
	Liabilities:
	Electric derivative instruments	$	91,998		$	15,230		$	107,228		$	18,073		$	19,239		$	37,312
	Natural gas derivative instruments	85,305			3,502			88,807			32,642			3,034			35,676
	Total liabilities	$	177,303		$	18,732		$	196,035		$	50,715		$	22,273		$	72,988
PUGET SOUND ENERGY, INC.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis
	Puget Sound Energy	Carrying / Fair Value									Carrying / Fair Value
		At December 31, 2014									At December 31, 2013
	(Dollars in Thousands)	Level 1			Level 2			Total			Level 1			Level 2			Total
	Assets:
	Cash and Cash Equivalents	$	37,466		$	—		$	37,466		$	44,111		$	—		$	44,111
	Restricted Cash	32,863			—			32,863			7,171			—			7,171
	Notes Receivable and Other	—			53,503			53,503			—			53,449			53,449
	Total assets	$	70,329		$	53,503		$	123,832		$	51,282		$	53,449		$	104,731
	Liabilities:
	Short-term debt	$	85,000		$	—		$	85,000		$	162,000		$	—		$	162,000
	Short-term debt owed to parent	—			28,933			28,933			—			29,598			29,598
	Total liabilities	$	85,000		$	28,933		$	113,933		$	162,000		$	29,598		$	191,598

Retirement_Benefits_Tables

Retirement Benefits (Tables)	12 Months Ended
	Dec. 31, 2014
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Schedule of Changes in Projected Benefit Obligations	The following tables summarize the Company’s change in benefit obligation, change in plan assets and amounts recognized in the Statements of Financial Position for the years ended December 31, 2014 and 2013:
	Puget Energy and	Qualified						SERP						Other
	Puget Sound Energy	Pension Benefits						Pension Benefits						Benefits
	(Dollars in Thousands)	2014			2013			2014			2013			2014			2013
	Change in benefit obligation:
	Benefit obligation at beginning of period	$	573,317		$	616,290		$	47,279		$	51,795		$	14,939		$	17,672
	Service cost	17,437			19,285			1,042			1,498			112			134
	Interest cost	28,039			24,754			2,310			2,045			684			664
	Amendment	—			—			—			478			—			—
	Actuarial loss (gain)	104,618			(48,559		)	7,162			(1,687		)	1,108			(2,240		)
	Benefits paid	(33,217		)	(38,453		)	(1,938		)	(6,850		)	(1,424		)	(1,536		)
	Medicare part D subsidy received	—			—			—			—			269			245
	Benefit obligation at end of period	$	690,194		$	573,317		$	55,855		$	47,279		$	15,688		$	14,939
Schedule of Changes in Fair Value of Plan Assets
	Puget Energy and	Qualified						SERP						Other
	Puget Sound Energy	Pension Benefits						Pension Benefits						Benefits
	(Dollars in Thousands)	2014			2013			2014			2013			2014			2013
	Change in plan assets:
	Fair value of plan assets at beginning of period	$	615,721		$	531,183		$	—		$	—		$	8,774		$	7,541
	Actual return on plan assets	25,669			102,591			—			—			522			1,861
	Employer contribution	18,000			20,400			1,938			6,850			488			908
	Benefits paid	(33,217		)	(38,453		)	(1,938		)	(6,850		)	(1,424		)	(1,536		)
	Fair value of plan assets at end of period	$	626,173		$	615,721		$	—		$	—		$	8,360		$	8,774
	Funded status at end of period	$	(64,021	)	$	42,404		$	(55,855	)	$	(47,279	)	$	(7,328	)	$	(6,165	)
Schedule of Amounts Recognized in Balance Sheet and Accumulated Other Comprehensive Income
	Puget Energy and	Qualified						SERP						Other
	Puget Sound Energy	Pension Benefits						Pension Benefits						Benefits
	(Dollars in Thousands)	2014			2013			2014			2013			2014			2013
	Amounts recognized in Statement of Financial Position consist of:
	Noncurrent assets	$	—		$	42,404		$	—		$	—		$	—		$	—
	Current liabilities	—			—			(4,386		)	(3,981		)	(355		)	(421		)
	Noncurrent liabilities	(64,021		)	—			(51,469		)	(43,298		)	(6,973		)	(5,744		)
	Net assets (liabilities)	$	(64,021	)	$	42,404		$	(55,855	)	$	(47,279	)	$	(7,328	)	$	(6,165	)
Schedule of Net Benefit Costs
	Puget Energy	Qualified									SERP									Other
		Pension Benefits									Pension Benefits									Benefits
	(Dollars in Thousands)	2014			2013			2012			2014			2013			2012			2014			2013			2012
	Components of net periodic benefit cost:
	Service cost	$	17,437		$	19,285		$	16,926		$	1,042		$	1,498		$	1,073		$	112		$	134		$	139
	Interest cost	28,039			24,754			25,986			2,310			2,045			2,152			684			664			751
	Expected return on plan assets	(42,464		)	(39,095		)	(36,203		)	—			—			—			(535		)	(436		)	(435		)
	Amortization of prior service cost (credit)	(1,980		)	(1,980		)	(1,980		)	42			(17		)	—			—			—			—
	Amortization of net loss	—			2,889			768			913			1,461			702			(393		)	69			53
	Net periodic benefit cost	$	1,032		$	5,853		$	5,497		$	4,307		$	4,987		$	3,927		$	(132	)	$	431		$	508
Schedule of Amounts Recognized in Other Comprehensive Income (Loss)
	Puget Energy	Qualified						SERP						Other
		Pension Benefits						Pension Benefits						Benefits
	(Dollars in Thousands)	2014			2013			2014			2013			2014			2013
	Other changes (pre-tax) in plan assets and benefit obligations recognized in other comprehensive income:
	Net loss (gain)	$	121,413		$	(112,055	)	$	7,162		$	(1,687	)	$	1,121		$	(3,665	)
	Amortization of net loss (gain)	—			(2,889		)	(913		)	(1,461		)	394			(70		)
	Prior service credit	—			—			—			478			—			—
	Amortization of prior service credit	1,980			1,980			(42		)	17			—			—
	Total change in other comprehensive income for year	$	123,393		$	(112,964	)	$	6,207		$	(2,653	)	$	1,515		$	(3,735	)
Schedule of Assumptions Used	In accounting for pension and other benefit obligations and costs under the plans, the following weighted-average actuarial assumptions were used by the Company:
		Qualified						SERP						Other
		Pension Benefits						Pension Benefits						Benefits
	Benefit Obligation Assumptions	2014		2013		2012		2014		2013		2012		2014		2013		2012
	Discount rate 1	4.25	%	5.1	%	4.15	%	4.25	%	5.1	%	4.15	%	4.25	%	5.1	%	4.15	%
	Rate of compensation increase	4.5	%	4.5	%	4.5	%	4.5	%	4.5	%	4.5	%	4.5	%	4.5	%	4.5	%
	Medical trend rate	—		—		—		—		—		—		5.7	%	6.8	%	7.5	%
	Benefit Cost Assumptions
	Discount rate	5.1	%	4.15	%	4.75	%	5.1	%	4.15	%	4.75	%	5.1	%	4.15	%	4.75	%
	Rate of plan assets	7.75	%	7.75	%	7.75	%	—		—		—		7	%	6.9	%	7.5	%
	Rate of compensation increase	4.5	%	4.5	%	4.5	%	4.5	%	4.5	%	4.5	%	4.5	%	4.5	%	4.5	%
	Medical trend rate	—		—		—		—		—		—		6.7	%	8.2	%	7.5	%
	_______________
	1	The Company calculates the present value of the pension liability using a discount rate of 4.25% which represents the single-rate equivalent of the AA rated corporate bond yield curve.
Schedule of Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates	A 1.0% change in the assumed medical inflation rate would have the following effects:
		2014						2013
	(Dollars in Thousands)	1% Increase			1% Decrease			1% Increase			1% Decrease
	Effect on post-retirement benefit obligation	$	47		$	(47	)	$	66		$	(66	)
	Effect on service and interest cost components	2			(2		)	3			(3		)
Schedule of Expected Benefit Payments	The expected total benefits to be paid under the next five years and the aggregate total to be paid for the five years thereafter are as follows:
	(Dollars in Thousands)	2015			2016			2017			2018			2019			2020-2024
	Qualified Pension total benefits	$	41,100		$	41,400		$	42,100		$	43,300		$	43,900		$	237,300
	SERP Pension total benefits	$	4,386		$	2,595		1,940			5,346			5,811			18,759
	Other Benefits total with Medicare Part D subsidy	$	1,080		$	1,136		$	1,113		$	1,085		$	1,062		$	5,935
	Other Benefits total without Medicare Part D subsidy	$	1,429		$	1,414		$	1,398		$	1,380		$	1,362		$	6,340
Schedule of Allocation of Plan Assets	The following table sets forth by level, within the fair value hierarchy, the qualified pension plan as of December 31, 2014 and 2013:
		Recurring Fair Value Measures												Recurring Fair Value Measures
		As of December 31, 2014												As of December 31, 2013
	(Dollars in Thousands)	Level 1			Level 2			Level 3			Total			Level 1			Level 2			Level 3			Total
	Assets:
	Equities:
	Non-US equity 1	$	71,026		$	74,131		$	—		$	145,157		$	76,188		$	78,816		$	—		$	155,004
	Domestic large cap equity 2	134,765			68,336			—			203,101			157,874			35,851			—			193,725
	Domestic small cap equity 3	59,657			—			—			59,657			62,867			—			—			62,867
	Total equities	265,448			142,467			—			407,915			296,929			114,667			—			411,596
	Tactical asset allocation 4	—			—			—			—			—			—			—			—
	Fixed income securities 5	72,331			67,182			—			139,513			135,007			—			—			135,007
	Absolute return 6	—			—			65,251			65,251			—			—			62,278			62,278
	Cash and cash equivalents 7	12,650			—			—			12,650			—			7,054			—			7,054
	Subtotal	$	350,429		$	209,649		$	65,251		$	625,329		$	431,936		$	121,721		$	62,278		$	615,935
	Net (payable) receivable	—			—			—			844			—			—			—			(417		)
	Accrued income	—			—			—			—			—			—			—			203
	Total assets										$	626,173											$	615,721
	_________________
	1	Non – US Equity investments are comprised of a (1) mutual fund; and a (2) commingled fund.  The investment in the mutual fund is valued using quoted market prices multiplied by the number of shares owned as of December 31, 2014.  The investment in the commingled fund is valued at the net asset value per share multiplied by the number of shares held as of December 31, 2014.
	2	Domestic large cap equity investments are comprised of (1) common stock, and a (2) commingled fund.  Investments in common stock are valued using quoted market prices multiplied by the number of shares owned as of December 31, 2014.  The investment in the commingled fund is valued at the net asset value per share multiplied by the number of shares held as of December 31, 2014.
	3	Domestic small cap equity investments are comprised of (1) common stock and a (2) mutual fund. The investments in common stock are valued using quoted market prices multiplied by the number of shares owned as of December 31, 2014. The investment in the mutual fund is valued using quoted market prices multiplied by the number of shares owned as of December 31, 2014.
	4	The tactical asset allocation investment is comprised of a commingled fund, which is valued at the net asset value per share multiplied by the number of shares held as of the measurement date.
	5	Fixed income securities consist of a mutual fund.  The investment in the mutual fund is valued using quoted market prices multiplied by the number of shares owned as of December 31, 2014.
	6	As of December 31, 2014 absolute return investments consist of two partnerships.  The partnerships are valued using the financial reports as of December 31, 2014.  These investments are a Level 3 under ASC 820 because the significant valuation inputs are primarily internal to the partnerships with little third party involvement.
	7	The investment consists of a money market fund, which is valued at the net asset value per share of $1.00 per unit as of December 31, 2014.  The money market fund invests primarily in commercial paper, notes, repurchase agreements, and other evidences of indebtedness which are payable on demand or short-term in nature.
	The following table sets forth by level, within the fair value hierarchy, the Other Benefits plan assets which consist of insurance benefits for retired employees, at fair value:
		Recurring Fair Value Measures									Recurring Fair Value Measures
		As of December 31, 2014									As of December 31, 2013
	(Dollars in Thousands)	Level 1			Level 2			Total			Level 1			Level 2			Total
	Assets:
	Mutual fund 1	$	8,301		$	—		$	8,301		$	8,703		$	—		$	8,703
	Cash equivalents 2	59			—			59			—			71			71
	Total assets	$	8,360		$	—		$	8,360		$	8,703		$	71		$	8,774
	_______________
	1	This is a publicly traded balanced mutual fund.  The fund seeks regular income, conservation of principal, and an opportunity for long-term growth of principal and income.  The fair value is determined by taking the number of shares owned by the plan, and multiplying by the market price as of December 31, 2014.
	2	This is a money market fund.  The money market fund investments are valued at the net asset value per share of $1.00 per unit as of December 31, 2014.  The money market fund invests primarily in commercial paper, notes, repurchase agreements, and other evidences of indebtedness which are payable on demand or short-term in nature.
	To obtain the desired return needed to fund the pension benefit plans, the Retirement Plan Committee has established investment allocation percentages by asset classes as follows:
		Allocation
	Asset Class	Minimum	Target	Maximum
	Domestic large cap equity	25%	31%	40%
	Domestic small cap equity	0%	9%	15%
	Non-U.S. equity	10%	25%	30%
	Fixed income	15%	25%	30%
	Real estate	0%	0%	10%
	Absolute return	5%	10%	15%
	Cash	0%	0%	5%
Schedule of Effect of Significant Unobservable Inputs, Changes in Plan Assets	Level 3 Roll-Forward
	The following table sets forth a reconciliation of changes in the fair value of the plan’s Level 3 assets:
		As of December 31, 2014									As of December 31, 2013
	(Dollars in Thousands)	Partnership			Mutual Funds			Total			Partnership			Mutual Funds			Total
	Balance at beginning of year	$	62,278		$	—		$	62,278		$	55,614		$	—		$	55,614
	Additional investments	—			—			—			—			—			—
	Distributions	—			—			—			—			—			—
	Realized losses on distributions	—			—			—			—			—			—
	Unrealized gains relating to instruments still held at the reporting date	2,973			—			2,973			6,664			—			6,664
	Transferred out of level 3 1	—			—			—			—			—			—
	Balance at end of year	$	65,251		$	—		$	65,251		$	62,278		$	—		$	62,278
	_________________
	1	The plan had no transfers between level 2 and level 1 during the years ended December 31, 2014 or 2013.
PUGET ENERGY
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Schedule of Amounts Recognized in Balance Sheet and Accumulated Other Comprehensive Income
	Puget Energy	Qualified						SERP						Other
		Pension Benefits						Pension Benefits						Benefits
	(Dollars in Thousands)	2014			2013			2014			2013			2014			2013
	Amounts recognized in Accumulated Other Comprehensive Income consist of:
	Net loss (gain)	$	55,471		$	(65,943	)	$	15,918		$	9,670		$	(1,457	)	$	(2,972	)
	Prior service cost (credit)	(13,782		)	(15,762		)	331			373			—			—
	Total	$	41,689		$	(81,705	)	$	16,249		$	10,043		$	(1,457	)	$	(2,972	)
PUGET SOUND ENERGY, INC.
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Schedule of Amounts Recognized in Balance Sheet and Accumulated Other Comprehensive Income
	Puget Sound Energy	Qualified						SERP						Other
		Pension Benefits						Pension Benefits						Benefits
	(Dollars in Thousands)	2014			2013			2014			2013			2014			2013
	Amounts recognized in Accumulated Other Comprehensive Income consist of:
	Net loss (gain)	$	247,331		$	138,324		$	19,751		$	14,050		$	(3,733	)	$	(5,556	)
	Prior service cost (credit)	(10,952		)	(12,525		)	339			383			3			6
	Total	$	236,379		$	125,799		$	20,090		$	14,433		$	(3,730	)	$	(5,550	)
Schedule of Net Benefit Costs
	Puget Sound Energy	Qualified									SERP									Other
		Pension Benefits									Pension Benefits									Benefits
	(Dollars in Thousands)	2014			2013			2012			2014			2013			2012			2014			2013			2012
	Components of net periodic benefit cost:
	Service cost	$	17,437		$	19,285		$	16,926		$	1,042		$	1,498		$	1,073		$	112		$	134		$	139
	Interest cost	28,039			24,753			25,986			2,310			2,045			2,152			684			664			751
	Expected return on plan assets	(43,252		)	(40,685		)	(41,533		)	—			—			—			(535		)	(436		)	(435		)
	Amortization of prior service cost (credit)	(1,573		)	(1,573		)	(1,573		)	44			(16		)	293			3			30			35
	Amortization of net loss(gain)	13,195			20,612			15,015			1,461			2,191			1,432			(702		)	(284		)	(245		)
	Amortization of transition obligation	—			—			—			—			—			—			—			—			50
	Net periodic benefit cost	$	13,846		$	22,392		$	14,821		$	4,857		$	5,718		$	4,950		$	(438	)	$	108		$	295
Schedule of Amounts Recognized in Other Comprehensive Income (Loss)
	Puget Sound Energy	Qualified						SERP						Other
		Pension Benefit						Pension Benefits						Benefits
	(Dollars in Thousands)	2014			2013			2014			2013			2014			2013
	Other changes (pre-tax) in plan assets and benefit obligations recognized in other comprehensive income:
	Net loss (gain)	$	122,202		$	(110,465	)	$	7,162		$	(1,687	)	$	1,121		$	(3,665	)
	Amortization of net (loss) gain	(13,195		)	(20,612		)	(1,461		)	(2,191		)	702			284
	Prior service cost (credit)	—			—			—			477			—			—
	Amortization of prior service cost (credit)	1,573			1,573			(44		)	16			(3		)	(30		)
	Amortization of transition obligation	—			—			—			—			—			—
	Total change in other comprehensive income for year	$	110,580		$	(129,504	)	$	5,657		$	(3,385	)	$	1,820		$	(3,411	)

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosures [Line Items]
Schedule of Components of Income Tax Expense (Benefit)	The details of income tax (benefit) expense are as follows:
	Puget Energy	Year Ended December 31,
	(Dollars in Thousands)	2014			2013			2012
	Charged to operating expenses:
	Current:
	Federal	$	—		$	—		$	4,268
	State	—			—			—
	Deferred:
	Federal	57,152			122,559			100,701
	State	(167		)	(151		)	(244		)
	Total income tax expense	$	56,985		$	122,408		$	104,725
Schedule of Effective Income Tax Rate Reconciliation
	Puget Energy	Year Ended December 31,
	(Dollars in Thousands)	2014			2013			2012
	Income taxes at the statutory rate	$	80,087		$	142,847		$	132,491
	Increase (decrease):
	Production tax credit	(23,073		)	(22,414		)	(22,188		)
	AFUDC excluded from taxable income	(3,790		)	(9,406		)	(16,543		)
	Capitalized interest	2,947			7,294			9,757
	Utility plant differences	7,090			9,527			8,674
	Treasury grant amortization	(8,808		)	(7,651		)	(1,007		)
	Tenaska gas contract	—			1			(4,687		)
	Other - net	2,532			2,210			(1,772		)
	Total income tax expense	$	56,985		$	122,408		$	104,725
	Effective tax rate	24.9		%	30		%	27.7		%
Schedule of Deferred Tax Assets and Liabilities	The Company’s deferred tax liability at December 31, 2014 and 2013 is composed of amounts related to the following types of temporary differences:
	Puget Energy	At December 31,
	(Dollars in Thousands)	2014			2013
	Utility plant and equipment	$	1,720,730		$	1,625,107
	Regulatory asset for income taxes	95,432			146,867
	Fair value of debt instruments	73,606			76,991
	Other deferred tax liabilities	200,124			202,189
	Subtotal deferred tax liabilities	2,089,892			2,051,154
	Net operating loss carryforward	(417,684		)	(374,606		)
	Production tax credit carryforward	(158,604		)	(135,531		)
	Regulatory liability on production tax credit	(84,344		)	(71,880		)
	Fair value of derivative instruments	(36,227		)	(7,166		)
	Other deferred tax assets	(32,121		)	(60,970		)
	Subtotal deferred tax assets	(728,980		)	(650,153		)
	Total	$	1,360,912		$	1,401,001
Schedule of Deferred Income Taxes by Balance Sheet Location	The above amounts have been classified in the Consolidated Balance Sheets as follows:
	Puget Energy	At December 31
	(Dollars in Thousands)	2014			2013
	Current deferred taxes	$	(161,445	)	$	(86,004	)
	Non-current deferred taxes	1,522,357			1,487,005
	Total	$	1,360,912		$	1,401,001
PUGET SOUND ENERGY, INC.
Income Tax Disclosures [Line Items]
Schedule of Components of Income Tax Expense (Benefit)
	Puget Sound Energy	Year Ended December 31,
	(Dollars in Thousands)	2014			2013			2012
	Charged to operating expenses:
	Current:
	Federal	$	—		$	—		$	4,268
	State	—			—			—
	Deferred:
	Federal	89,342			160,886			145,040
	State	—			—			—
	Total income tax expense	$	89,342		$	160,886		$	149,308
Schedule of Effective Income Tax Rate Reconciliation
	Puget Sound Energy	Year Ended December 31,
	(Dollars in Thousands)	2014			2013			2012
	Income taxes at the statutory rate	$	114,084		$	180,955		$	176,917
	Increase (decrease):
	Production tax credit	(23,073		)	(22,414		)	(22,188		)
	AFUDC excluded from taxable income	(3,790		)	(9,406		)	(16,543		)
	Capitalized interest	2,947			7,294			9,757
	Utility plant differences	7,090			9,527			8,674
	Treasury grant amortization	(8,808		)	(7,651		)	(1,007		)
	Tenaska gas contract	—			1			(4,687		)
	Other - net	892			2,580			(1,615		)
	Total income tax expense	$	89,342		$	160,886		$	149,308
	Effective tax rate	27.4		%	31.1		%	29.5		%
Schedule of Deferred Tax Assets and Liabilities
	Puget Sound Energy	At December 31,
	(Dollars In Thousands)	2014			2013
	Utility plant and equipment	$	1,720,730		$	1,625,107
	Regulatory asset for income taxes	94,913			146,350
	Other deferred tax liabilities	171,380			131,977
	Subtotal deferred tax liabilities	1,987,023			1,903,434
	Net operating loss carryforward	(181,514		)	(173,068		)
	Production tax credit carryforward	(158,604		)	(135,531		)
	Regulatory liability on production tax credit	(84,344		)	(71,880		)
	Fair value of derivative instruments	(39,067		)	(9,988		)
	Other deferred tax assets	(82,084		)	(69,175		)
	Subtotal deferred tax assets	(545,613		)	(459,642		)
	Total	$	1,441,410		$	1,443,792
Schedule of Deferred Income Taxes by Balance Sheet Location
	Puget Sound Energy	At December 31
	(Dollars in Thousands)	2014			2013
	Current deferred taxes	$	(208,447	)	$	(141,058	)
	Non-current deferred taxes	1,649,857			1,584,850
	Total	$	1,441,410		$	1,443,792

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Schedule of Long-term Contracts for Purchase of Electric Power	The Company's expenses under these PUD contracts were as follows for the years ended December 31:
	(Dollars in Thousands)				2014			2013			2012
	PUD contract costs				$	69,661		$	63,365		$	70,188
	As of December 31, 2014, the Company purchased portions of the power output of the PUDs' projects as set forth in the following table:
			Company's Current Share of
	(Dollars in Thousands)	Contract	Percent of		Megawatt Capacity		Estimated 2015 Costs			2015 Debt Service Costs			Interest included in 2015 Debt Service Costs			Debt Outstanding
		Expiration	Output
	Chelan County PUD:
	Rock Island Project	2031	25	%	156		$	29,854		$	11,009		$	6,174		$	98,191
	Rocky Reach Project	2031	25	%	325		27,583			8,245			3,343			53,299
	Douglas County PUD:
	Wells Project	2018	29.9	%	251		17,277			9,383			2,597			64,931
	Grant County PUD:
	Priest Rapids Development	2052	0.6	%	8		3,689			2,087			1,245			19,828
	Wanapum Development	2052	0.6	%	9		3,689			2,087			1,245			19,828
	Total				749		$	82,092		$	32,811		$	14,604		$	256,077
Schedule of Long-term Purchase Commitments	These contracts have varying terms and may include escalation and termination provisions.
	(Dollars in Thousands)	2015			2016			2017			2018			2019			Thereafter		Total
	Columbia River projects	$	73,023		$	75,360		$	74,851		$	65,981		$	53,837		$	644,666	$	987,718
	Other utilities	16,136			18,884			11,823			1,257			890			—		48,990
	Non-utility contracts	117,372			153,863			199,056			204,292			209,699			1,354,191		2,238,473
	Total	$	206,531		$	248,107		$	285,730		$	271,530		$	264,426		$	1,998,857	$	3,275,181
	The quantified obligations are based on the FERC and NEB (National Energy Board) currently authorized rates, which are subject to change.
	Demand Charge Obligations	2015			2016			2017			2018			2019			Thereafter		Total
	(Dollars in Thousands)
	Firm transportation service	$	154,121		$	147,424		$	144,751		$	131,484		$	112,249		$	373,958	$	1,063,987
	Firm storage service	6,528			5,337			5,209			1,407			1,535			1,258		21,274
	Total	$	160,649		$	152,761		$	149,960		$	132,891		$	113,784		$	375,216	$	1,085,261
	The following table summarizes the Company’s estimated obligations for service contracts through the terms of its existing contracts.
	Service Contract Obligations	2015			2016			2017			2018			2019			Thereafter		Total
	(Dollars in Thousands)
	Energy production service contracts	$	32,979		$	15,650		$	5,558		$	4,064		$	2,372		$	23,443	$	84,066
	Automated meter reading system	25,402			16,081			13,362			13,996			14,602			51,986		135,429
	Total	$	58,381		$	31,731		$	18,920		$	18,060		$	16,974		$	75,429	$	219,495

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	The following tables set forth the components of the Company’s accumulated other comprehensive income (loss) at:
	Puget Energy	December 31,
	(Dollars in Thousands)	2014			2013
	Net unrealized loss on energy derivative instruments	$	(333	)	$	(705	)
	Net unrealized loss on interest rate swaps	—			(94		)
	Net unrealized loss and prior service cost on pension plans	(36,710		)	48,514
	Total Puget Energy, net of tax	$	(37,043	)	$	47,715
	Puget Sound Energy	December 31,
	(Dollars in Thousands)	2014			2013
	Net unrealized loss on energy derivative instruments	$	(686	)	$	(2,027	)
	Net unrealized loss on treasury interest rate swaps	(5,990		)	(6,307		)
	Net unrealized loss and prior service cost on pension plans	(164,281		)	(87,405		)
	Total PSE, net of tax	$	(170,957	)	$	(95,739	)
	The following tables present the changes in the Company’s accumulated other comprehensive income (loss) (AOCI) by component for the years ended December 31, 2014, 2013 and 2012, respectively.
	Puget Energy	Net unrealized gain (loss) and prior service cost on pension plans			Net unrealized gain (loss) on energy derivative instruments			Net unrealized gain (loss) on interest rate swaps
	Changes in AOCI, net of tax
	(Dollars in Thousands)										Total
	Balance at December 31, 2011	$	(15,195	)	$	(1,113	)	$	(14,599	)	$	(30,907	)
	Other comprehensive income (loss) before reclassifications	(13,574		)	—			—			(13,574		)
	Amounts reclassified from accumulated other comprehensive income (loss), net of tax	(296		)	371			11,577			11,652
	Net current-period other comprehensive income (loss)	(13,870		)	371			11,577			(1,922		)
	Balance at December 31, 2012	$	(29,065	)	$	(742	)	$	(3,022	)	$	(32,829	)
	Other comprehensive income (loss) before reclassifications	76,004			—			—			76,004
	Amounts reclassified from accumulated other comprehensive income (loss), net of tax	1,575			37			2,928			4,540
	Net current-period other comprehensive income (loss)	77,579			37			2,928			80,544
	Balance at December 31, 2013	$	48,514		$	(705	)	$	(94	)	$	47,715
	Other comprehensive income (loss) before reclassifications	(84,301		)	—			—			(84,301		)
	Amounts reclassified from accumulated other comprehensive income (loss), net of tax	(923		)	372			94			(457		)
	Net current-period other comprehensive income (loss)	(85,224		)	372			94			(84,758		)
	Balance at December 31, 2014	$	(36,710	)	$	(333	)	$	—		$	(37,043	)
	Puget Sound Energy	Net unrealized gain (loss) and prior service cost on pension plans			Net unrealized gain (loss) on energy derivative instruments			Net unrealized gain (loss) on treasury interest rate swaps
	Changes in AOCI, net of tax
	(Dollars in Thousands)										Total
	Balance at December 31, 2011	$	(168,704	)	$	(12,934	)	$	(6,941	)	$	(188,579	)
	Other comprehensive income (loss) before reclassifications	(17,049		)	—			—			(17,049		)
	Amounts reclassified from accumulated other comprehensive income (loss), net of tax	9,755			8,358			317			18,430
	Net current-period other comprehensive income (loss)	(7,294		)	8,358			317			1,381
	Balance at December 31, 2012	$	(175,998	)	$	(4,576	)	$	(6,624	)	$	(187,198	)
	Other comprehensive income (loss) before reclassifications	74,969			—			—			74,969
	Amounts reclassified from accumulated other comprehensive income (loss), net of tax	13,624			2,549			317			16,490
	Net current-period other comprehensive income (loss)	88,593			2,549			317			91,459
	Balance at December 31, 2013	$	(87,405	)	$	(2,027	)	$	(6,307	)	$	(95,739	)
	Other comprehensive income (loss) before reclassifications	(84,955		)	—			—			(84,955		)
	Amounts reclassified from accumulated other comprehensive income (loss), net of tax	8,079			1,341			317			9,737
	Net current-period other comprehensive income (loss)	(76,876		)	1,341			317			(75,218		)
	Balance at December 31, 2014	$	(164,281	)	$	(686	)	$	(5,990	)	$	(170,957	)
Reclassification out of Accumulated Other Comprehensive Income [Table Text Block]	Details about these reclassifications out of accumulated other comprehensive income (loss) for the years ended December 31, 2014, 2013 and 2012, respectively, are as follows:
	Puget Energy
	(Dollars in Thousands)
	Details about accumulated other comprehensive income (loss) components	Affected line item in the statement where net income (loss) is presented	Amount reclassified from accumulated
			other comprehensive income (loss)
			2014			2013			2012
	Net unrealized gain (loss) and prior service cost on pension plans:
	Amortization of prior service cost	(a)	1,938			1,997			1,980
	Amortization of net gain (loss)	(a)	(519		)	(4,420		)	(1,524		)
		Total before tax	1,419			(2,423		)	456
		Tax (expense) or benefit	(496		)	848			(160		)
		Net of Tax	$	923		$	(1,575	)	$	296
	Net unrealized gain (loss) on energy derivative instruments:
	Commodity contracts: Electric derivatives	Electric generation fuel	—			—			100
		Purchased electricity	(572		)	(57		)	(671		)
		Total before tax	(572		)	(57		)	(571		)
		Tax (expense) or benefit	200			20			200
		Net of Tax	$	(372	)	$	(37	)	$	(371	)
	Net unrealized gain (loss) on interest rate swaps:
	Interest rate contracts	Interest expense	$	(144	)	$	(4,505	)	$	(17,811	)
		Tax (expense) or benefit	50			1,577			6,234
		Net of Tax	$	(94	)	$	(2,928	)	$	(11,577	)
	Total reclassification for the period	Net of Tax	$	457		$	(4,540	)	$	(11,652	)
	__________
	(a)	These accumulated other comprehensive income components are included in the computation of net periodic pension cost (see Note 12 for additional details).
	Puget Sound Energy
	(Dollars in Thousands)
	Details about accumulated other comprehensive income (loss) components	Affected line item in the statement where net income (loss) is presented	Amount reclassified from accumulated
			other comprehensive income (loss)
			2014			2013			2012
	Net unrealized gain (loss) and prior service cost on pension plans:
	Amortization of prior service cost	(a)	$	1,526		$	1,559		$	1,245
	Amortization of net gain (loss)	(a)	(13,954		)	(22,519		)	(16,203		)
	Amortization of transition obligation	(a)	—			—			(50		)
		Total before tax	(12,428		)	(20,960		)	(15,008		)
		Tax (expense) or benefit	4,349			7,336			5,253
		Net of tax	$	(8,079	)	$	(13,624	)	$	(9,755	)
	Net unrealized gain (loss) on energy derivative instruments:
	Commodity contracts: Electric derivatives	Electric generation fuel	—			—			97
		Purchased electricity	(2,063		)	(3,922		)	(12,955		)
		Total before tax	(2,063		)	(3,922		)	(12,858		)
		Tax (expense) or benefit	722			1,373			4,500
		Net of Tax	$	(1,341	)	$	(2,549	)	$	(8,358	)
	Net unrealized gain (loss) on treasury interest rate swaps:
	Interest rate contracts	Interest expense	(488		)	(488		)	(488		)
		Tax (expense) or benefit	171			171			171
		Net of Tax	$	(317	)	$	(317	)	$	(317	)
	Total reclassification for the period	Net of Tax	$	(9,737	)	$	(16,490	)	$	(18,430	)
	__________
	(a)	These accumulated other comprehensive income components are included in the computation of net periodic pension cost (see Note 12 for additional details).

SUPPLEMENTAL_QUARTERLY_FINANCI1

SUPPLEMENTAL QUARTERLY FINANCIAL DATA (Tables)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	The following unaudited amounts, in the opinion of the Company, include all adjustments (consisting of normal recurring adjustments) necessary for a fair statement of the results of operations for the interim periods.  Quarterly amounts vary during the year due to the seasonal nature of the utility business.
	Puget Energy	2014 Quarter
	(Unaudited; Dollars in Thousands)	First		Second		Third			Fourth
	Operating revenue	$	1,025,375	$	662,916	$	593,715		$	831,165
	Operating income	236,301		145,266		65,069			131,215
	Net income (loss)	107,592		41,113		(12,958		)	36,088
		2013 Quarter
	(Unaudited; Dollars in Thousands)	First		Second		Third			Fourth
	Operating revenue	$	999,818	$	642,486	$	598,348		$	946,645
	Operating income	317,735		95,081		100,043			242,301
	Net income (loss)	167,475		905		8,540			108,808
	Puget Sound Energy	2014 Quarter
	(Unaudited; Dollars in Thousands)	First		Second		Third			Fourth
	Operating revenue	$	1,025,375	$	662,916	$	593,951		$	833,881
	Operating income	232,977		142,185		62,317			131,214
	Net income (loss)	121,083		57,834		3,057			54,640
		2013 Quarter
	(Unaudited; Dollars in Thousands)	First		Second		Third			Fourth
	Operating revenue	$	999,707	$	642,486	$	598,348		$	946,794
	Operating income	310,587		91,094		96,085			237,808
	Net income (loss)	179,938		26,663		26,605			122,923

Summary_of_Significant_Account3

Summary of Significant Accounting Policies (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Feb. 06, 2009
	unit
Accounting Policies
Goodwill	$1,656,513,000	$1,656,513,000			$1,700,000,000
Number of reportable segments	1
Cash and Cash Equivalents
Cash and Cash Equivalents, at Carrying Value	37,527,000	44,302,000	135,542,000	37,235,000
Cash equivalents	1,800,000	2,600,000
Revenue Recognition
Excise taxes collected	231,700,000	243,900,000	244,200,000
Allowance for Doubtful Accounts
Allowance for doubtful accounts	7,385,000	9,932,000
Self Insurance [Abstract]
Public Utilities, Rate Case, Deferred Storm Costs Threshold	8,000,000
Electric Transmission
Accounting Policies
Annual depreciation provision	2.80%	2.80%	2.90%
Gas Transmission Equipment
Accounting Policies
Annual depreciation provision	3.40%	3.40%	3.40%
Common Plant
Accounting Policies
Annual depreciation provision	8.50%	11.40%	11.60%
PUGET SOUND ENERGY, INC.
Accounting Policies
Area of service territory (sqmi)	6,000
Cash and Cash Equivalents
Cash and Cash Equivalents, at Carrying Value	37,466,000	44,111,000	135,530,000	31,010,000
Allowance for Doubtful Accounts
Allowance for doubtful accounts	$7,472,000	$7,385,000

Summary_of_Significant_Account4

Summary of Significant Accounting Policies - AFUDC (Details)	6 Months Ended	12 Months Ended	14 Months Ended	25 Months Ended
	Dec. 31, 2013	Dec. 31, 2014	Jun. 30, 2013	13-May-12
Regulatory Assets [Line Items]
Public Utilities, Property, Plant and Equipment, Non-project Electric Utility Plant, Estimated Useful Life Average		30 years
Washington Commission AFUDC Rates	7.77%		7.80%	8.10%

Summary_of_Significant_Account5

Summary of Significant Accounting Policies - Accumulated Other Comprehensive Income (Loss) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Accumulated Other Comprehensive Income (Loss)
Net unrealized loss on energy derivative instruments	($333)	($705)
Net unrealized loss on interest rate swaps	0	-94
Net unrealized loss and prior service cost on pension plans	-36,710	48,514
Accumulated other comprehensive income (loss), net of tax	-37,043	47,715
PUGET SOUND ENERGY, INC.
Accumulated Other Comprehensive Income (Loss)
Net unrealized loss on energy derivative instruments	-686	-2,027
Net unrealized loss on interest rate swaps	-5,990	-6,307
Net unrealized loss and prior service cost on pension plans	-164,281	-87,405
Accumulated other comprehensive income (loss), net of tax	($170,957)	($95,739)

Regulation_and_Rates_Schedule_

Regulation and Rates Schedule of Allowed Return on the Net Regulatory Assets and Liabilities (Details)	6 Months Ended	14 Months Ended	25 Months Ended
	Dec. 31, 2013	Jun. 30, 2013	13-May-12
Regulated Operations [Abstract]
Regulated Utility, Allowed Rate of Return on Net Regulatory Assets and Liabilities	7.77%	7.80%	8.10%
Regulated Utility, After-tax Allowed Rate of Return on Net Regulatory Assets and Liabilities	6.69%	6.71%	6.90%

Regulation_and_Rates_Net_regul

Regulation and Rates Net regulatory assets and liabilities (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
PUGET SOUND ENERGY, INC. | Cost of removal
Regulatory Assets [Line Items]
Regulatory Liabilities	($313,088)	[1]	($269,536)	[1]
PUGET SOUND ENERGY, INC. | Deferred income taxes
Regulatory Assets [Line Items]
Regulatory Liabilities	-93,616	[2]	-93,618	[2]
PUGET SOUND ENERGY, INC. | PGA payable
Regulatory Assets [Line Items]
Net Regulatory Assets, Remaining Amortization Period	1 year
Regulatory Liabilities	0		-5,938
PUGET SOUND ENERGY, INC. | PCA mechanism
Regulatory Assets [Line Items]
Regulatory Liabilities	0	[3]	-5,345	[3]
PUGET SOUND ENERGY, INC. | Decoupling over-collection
Regulatory Assets [Line Items]
Net Regulatory Assets, Remaining Amortization Period	2 years
Regulatory Liabilities	-12,582		-20,535
PUGET SOUND ENERGY, INC. | Summit purchase option buy-out
Regulatory Assets [Line Items]
Net Regulatory Assets, Remaining Amortization Period	5 years 9 months 18 days
Regulatory Liabilities	-9,188		-10,763
PUGET SOUND ENERGY, INC. | Deferred gain on Jefferson County sale
Regulatory Assets [Line Items]
Regulatory Liabilities	-4,731		-60,844
PUGET SOUND ENERGY, INC. | Deferred credit on Biogas sale
Regulatory Assets [Line Items]
Net Regulatory Assets, Remaining Amortization Period	1 year
Regulatory Liabilities	-1,445		-10,908
PUGET SOUND ENERGY, INC. | Deferred credit on gas pipeline capacity
Regulatory Assets [Line Items]
Net Regulatory Assets, Remaining Amortization Period, Max	3 years 9 months 18 days
Regulatory Liabilities	-3,564		-4,508
PUGET SOUND ENERGY, INC. | Renewable energy credits
Regulatory Assets [Line Items]
Net Regulatory Assets, Remaining Amortization Period	1 year
Regulatory Liabilities	-2,383		-5,820
PUGET SOUND ENERGY, INC. | Treasury grants
Regulatory Assets [Line Items]
Net Regulatory Assets, Remaining Amortization Period, Max	44 years
Regulatory Liabilities	-180,496		-203,889
PUGET SOUND ENERGY, INC. | Treasury grant amortization deferral [Member]
Regulatory Assets [Line Items]
Net Regulatory Assets, Remaining Amortization Period, Max	4 years
Regulatory Liabilities	-8,197		0
PUGET SOUND ENERGY, INC. | Various other regulatory liabilities
Regulatory Assets [Line Items]
Net Regulatory Assets, Remaining Amortization Period, Max	4 years
Regulatory Liabilities	-6,092		-5,755
PUGET SOUND ENERGY, INC. | Liabilities, Total
Regulatory Assets [Line Items]
Regulatory Liabilities	-635,382	[4]	-697,459	[4]
PUGET SOUND ENERGY, INC. | Net Regulatory Assets
Regulatory Assets [Line Items]
Net Regulatory Assets	352,020		198,273
PUGET SOUND ENERGY, INC. | Electron Unrecovered Loss
Regulatory Assets [Line Items]
Regulatory Assets	14,008		0
Net Regulatory Assets, Remaining Amortization Period	4 years
PUGET SOUND ENERGY, INC. | Decoupling Under-Collection
Regulatory Assets [Line Items]
Regulatory Assets	55,363		0
PUGET SOUND ENERGY, INC. | PGA deferral of unrealized losses on derivative instruments
Regulatory Assets [Line Items]
Regulatory Assets	69,280	[3]	27,555	[3]
PUGET SOUND ENERGY, INC. | Chelan PUD contract initiation
Regulatory Assets [Line Items]
Regulatory Assets	119,316		126,404
Net Regulatory Assets, Remaining Amortization Period	16 years 9 months 18 days
PUGET SOUND ENERGY, INC. | Storm damage costs electric
Regulatory Assets [Line Items]
Regulatory Assets	118,824		116,328
Net Regulatory Assets, Remaining Amortization Period, Max	4 years
PUGET SOUND ENERGY, INC. | Environmental remediation
Regulatory Assets [Line Items]
Regulatory Assets	66,018	[3]	57,342	[3]
PUGET SOUND ENERGY, INC. | Baker Dam Licensing Operating Maintenance Costs [Member]
Regulatory Assets [Line Items]
Regulatory Assets	61,577		57,270
Net Regulatory Assets, Remaining Amortization Period	44 years
PUGET SOUND ENERGY, INC. | Snoqualmie Licensing Operating Maintenance Costs
Regulatory Assets [Line Items]
Regulatory Assets	9,202		10,881
Net Regulatory Assets, Remaining Amortization Period	30 years
PUGET SOUND ENERGY, INC. | Colstrip common property
Regulatory Assets [Line Items]
Regulatory Assets	6,764		7,479
Net Regulatory Assets, Remaining Amortization Period	9 years 6 months
PUGET SOUND ENERGY, INC. | Deferred income taxes
Regulatory Assets [Line Items]
Regulatory Assets	94,913	[3]	146,350	[3]
PUGET SOUND ENERGY, INC. | Deferred Washington Commission AFUDC
Regulatory Assets [Line Items]
Regulatory Assets	53,709		55,495
Net Regulatory Assets, Remaining Amortization Period, Max	35 years
PUGET SOUND ENERGY, INC. | Energy Conservation Costs [Member]
Regulatory Assets [Line Items]
Regulatory Assets	42,374		35,987
Net Regulatory Assets, Remaining Amortization Period, Max	2 years
PUGET SOUND ENERGY, INC. | Unamortized loss on reacquired debt
Regulatory Assets [Line Items]
Regulatory Assets	35,667		37,832
Net Regulatory Assets, Remaining Amortization Period, Max	21 years 6 months
PUGET SOUND ENERGY, INC. | White River relicensing and other costs
Regulatory Assets [Line Items]
Regulatory Assets	26,685		28,190
Net Regulatory Assets, Remaining Amortization Period	17 years 10 months 24 days
PUGET SOUND ENERGY, INC. | Mint Farm ownership and operating costs
Regulatory Assets [Line Items]
Regulatory Assets	20,320		22,320
Net Regulatory Assets, Remaining Amortization Period	10 years 3 months 18 days
PUGET SOUND ENERGY, INC. | Investment in Bonneville Exchange power contract
Regulatory Assets [Line Items]
Regulatory Assets	8,816		12,343
Net Regulatory Assets, Remaining Amortization Period	2 years 6 months
PUGET SOUND ENERGY, INC. | Ferndale
Regulatory Assets [Line Items]
Regulatory Assets	19,232		22,811
Net Regulatory Assets, Remaining Amortization Period	4 years 9 months 18 days
PUGET SOUND ENERGY, INC. | Lower Snake River
Regulatory Assets [Line Items]
Regulatory Assets	86,275		92,924
Net Regulatory Assets, Remaining Amortization Period, Max	22 years 4 months
PUGET SOUND ENERGY, INC. | Snoqualmie
Regulatory Assets [Line Items]
Regulatory Assets	6,798		8,009
Net Regulatory Assets, Remaining Amortization Period	3 years 9 months
PUGET SOUND ENERGY, INC. | Property tax tracker
Regulatory Assets [Line Items]
Regulatory Assets	32,253		22,134
PUGET SOUND ENERGY, INC. | PCA mechanism
Regulatory Assets [Line Items]
Regulatory Assets	4,623	[3]	0	[3]
PUGET SOUND ENERGY, INC. | Various other regulatory assets
Regulatory Assets [Line Items]
Regulatory Assets	14,312		8,078
PUGET SOUND ENERGY, INC. | Assets, Total
Regulatory Assets [Line Items]
Regulatory Assets	987,402	[4]	895,732	[4]
PUGET SOUND ENERGY, INC. | PGA receivable [Domain]
Regulatory Assets [Line Items]
Regulatory Assets	21,073		0
Net Regulatory Assets, Remaining Amortization Period	1 year
PUGET ENERGY | Regulatory liabilities related to power contracts
Regulatory Assets [Line Items]
Net Regulatory Assets, Remaining Amortization Period, Max	37 years
Regulatory Liabilities	-391,389		-443,065
PUGET ENERGY | Various other regulatory liabilities
Regulatory Assets [Line Items]
Regulatory Liabilities	-2,820		-2,884
PUGET ENERGY | Liabilities, Total
Regulatory Assets [Line Items]
Regulatory Liabilities	-1,029,591		-1,143,408
PUGET ENERGY | Net Regulatory Assets
Regulatory Assets [Line Items]
Net Regulatory Assets	-11,812		-213,406
PUGET ENERGY | Requlatory Assets Related to Power Contracts
Regulatory Assets [Line Items]
Regulatory Assets	29,816		33,753
Net Regulatory Assets, Remaining Amortization Period, Max	22 years
PUGET ENERGY | Various other regulatory assets
Regulatory Assets [Line Items]
Regulatory Assets	561		517
PUGET ENERGY | Assets, Total
Regulatory Assets [Line Items]
Regulatory Assets	$1,017,779		$930,002
Maximum | PUGET SOUND ENERGY, INC. | Deferred gain on Jefferson County sale
Regulatory Assets [Line Items]
Net Regulatory Assets, Remaining Amortization Period	1 year
Maximum | PUGET SOUND ENERGY, INC. | Decoupling Under-Collection
Regulatory Assets [Line Items]
Net Regulatory Assets, Remaining Amortization Period	2 years
Maximum | PUGET SOUND ENERGY, INC. | Property tax tracker
Regulatory Assets [Line Items]
Net Regulatory Assets, Remaining Amortization Period	2 years
[1]	The balance is dependent upon the cost of removal of underlying assets and the life of utility plant.
[2]	Amortization will begin once PTCs are utilized by PSE on its tax return.
[3]	Amortization periods vary depending on timing of underlying transactions or awaiting regulatory approval in a future Washington Commission rate proceeding.
[4]	Puget Energy’s regulatory assets and liabilities include purchase accounting adjustments under ASC 805 as a result of the merger.

Regulation_and_Rates_Rate_Adju

Regulation and Rates Rate Adjustments (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jul. 01, 2013	1-May-14	14-May-12	Jun. 28, 2012	Dec. 01, 2014	23-May-14	Nov. 01, 2013	Jan. 02, 2014	Apr. 02, 2011	Nov. 01, 2014	Nov. 01, 2012	Nov. 01, 2011	Mar. 30, 2013	Sep. 11, 2014	Mar. 28, 2014
Regulation and Rates [Line Items]
Treasury grant payment received	$107,876,000	$0	$205,261,000
Public Utilities, Rate Case, Approved Effective Weighted Cost of Capital				7.77%
Public Utilities, Rate Case, Approved Effective Common Equity in Capital Structure				48.00%
Public Utilities, Rate Case, Approved Effective Return on Equity				9.80%
Electric
Regulation and Rates [Line Items]
Public Utilities, Rate Case, Approved Effective Annual Rate Percentage Increase (Decrease)					0.50%
Public Utilities, Rate Case, Approved Effective Weighted Cost of Capital						7.80%
Public Utilities, Rate Case, Approved Effective Common Equity in Capital Structure						48.00%
Public Utilities, Rate Case, Approved Effective Return on Equity						9.80%
Gas
Regulation and Rates [Line Items]
Public Utilities, Rate Case, Approved Effective Weighted Cost of Capital						7.80%
Public Utilities, Rate Case, Approved Effective Common Equity in Capital Structure						48.00%
Public Utilities, Rate Case, Approved Effective Return on Equity						9.80%
Accounting Petition, Approved Effective Increase (Decrease) to Revenue							6,900,000
Accounting Petition, Approved Effective Increase (Decrease) to Conservation Amortization Expense							6,600,000
Energy Conservation Costs [Member] | Electric
Regulation and Rates [Line Items]
Public Utilities, Rate Case, Approved Effective Annual Rate Increase (Decrease)					12,200,000
Public Utilities, Rate Case, Approved Effective Annual Rate Percentage Increase (Decrease)					0.50%
Energy Conservation Costs [Member] | Gas
Regulation and Rates [Line Items]
Public Utilities, Rate Case, Approved Effective Annual Rate Increase (Decrease)					300,000
Power Cost Only Rate Case (PCORC) | Electric
Regulation and Rates [Line Items]
Public Utilities, Rate Case, Approved Effective Annual Rate Increase (Decrease)								-19,400,000	-9,600,000	-10,500,000
Public Utilities, Rate Case, Approved Effective Annual Rate Percentage Increase (Decrease)								-0.90%	-0.50%	-0.50%
Decoupling Mechanism | Electric
Regulation and Rates [Line Items]
Public Utilities, Rate Case, Approved Effective Annual Rate Increase (Decrease)				21,400,000	10,600,000
Public Utilities, Rate Case, Approved Effective Annual Rate Percentage Increase (Decrease)				1.00%	0.50%
Decoupling Mechanism | Gas
Regulation and Rates [Line Items]
Public Utilities, Rate Case, Approved Effective Annual Rate Increase (Decrease)				10,800,000	-1,000,000
Public Utilities, Rate Case, Approved Effective Annual Rate Percentage Increase (Decrease)				1.10%	-0.10%
Property tax tracker | Electric
Regulation and Rates [Line Items]
Public Utilities, Rate Case, Approved Effective Annual Rate Increase (Decrease)					11,000,000
Public Utilities, Rate Case, Approved Effective Annual Rate Percentage Increase (Decrease)					0.50%
Property tax tracker | Gas
Regulation and Rates [Line Items]
Public Utilities, Rate Case, Approved Effective Annual Rate Increase (Decrease)					5,600,000
Public Utilities, Rate Case, Approved Effective Annual Rate Percentage Increase (Decrease)					0.60%
Expedited Rate Filing | Electric
Regulation and Rates [Line Items]
Public Utilities, Rate Case, Approved Effective Annual Rate Increase (Decrease)				30,700,000
Public Utilities, Rate Case, Approved Effective Annual Rate Percentage Increase (Decrease)				1.50%							3.00%
Expedited Rate Filing | Gas
Regulation and Rates [Line Items]
Public Utilities, Rate Case, Approved Effective Annual Rate Increase (Decrease)				-2,000,000
Public Utilities, Rate Case, Approved Effective Annual Rate Percentage Increase (Decrease)				-0.20%							2.20%
General Rate Case | Electric
Regulation and Rates [Line Items]
Public Utilities, Rate Case, Approved Effective Annual Rate Increase (Decrease)						63,300,000
Public Utilities, Rate Case, Approved Effective Annual Rate Percentage Increase (Decrease)						3.20%
General Rate Case | Gas
Regulation and Rates [Line Items]
Public Utilities, Rate Case, Approved Effective Annual Rate Increase (Decrease)						13,400,000						19,000,000
Public Utilities, Rate Case, Approved Effective Annual Rate Percentage Increase (Decrease)						1.30%						1.80%
Purchased Gas Adjustment (PGA) | Gas
Regulation and Rates [Line Items]
Public Utilities, Rate Case, Approved Effective Annual Rate Increase (Decrease)										4,000,000			-23,300,000	-77,000,000	-43,500,000
Public Utilities, Rate Case, Approved Effective Annual Rate Percentage Increase (Decrease)										0.40%			-2.50%	-7.70%	-4.30%
Jefferson County Public Utility District
Regulation and Rates [Line Items]
Property, Plant and Equipment, Net																46,700,000
Significant Acquisitions and Disposals, Gain (Loss) on Sale or Disposal, Pretax																60,000,000
PUGET SOUND ENERGY, INC.
Regulation and Rates [Line Items]
Treasury grant payment received	107,876,000	0	205,261,000
PUGET SOUND ENERGY, INC. | Jefferson County Public Utility District
Regulation and Rates [Line Items]
Significant Acquisitions and Disposals, Gain (Loss) on Sale or Disposal, Pretax																45,000,000	7,500,000	3,000,000
Customers | Jefferson County Public Utility District
Regulation and Rates [Line Items]
Significant Acquisitions and Disposals, Gain (Loss) on Sale or Disposal, Pretax																$15,000,000	$52,700,000	$57,000,000

Regulation_and_Rates_Power_Cos

Regulation and Rates Power Cost Adjustment Mechanism (Details)	Dec. 31, 2014
Plus/Minus $20 million | Customers’ Share
Regulation and Rates [Line Items]
Annual Power Cost Variability	0.00%
Plus/Minus $20 million | Company's Share
Regulation and Rates [Line Items]
Annual Power Cost Variability	100.00%
Plus/Minus $20 million - $40 million | Customers’ Share
Regulation and Rates [Line Items]
Annual Power Cost Variability	50.00%
Plus/Minus $20 million - $40 million | Company's Share
Regulation and Rates [Line Items]
Annual Power Cost Variability	50.00%
Plus/Minus $40 million - $120 million | Customers’ Share
Regulation and Rates [Line Items]
Annual Power Cost Variability	90.00%
Plus/Minus $40 million - $120 million | Company's Share
Regulation and Rates [Line Items]
Annual Power Cost Variability	10.00%
Plus/Minus $120 million | Customers’ Share
Regulation and Rates [Line Items]
Annual Power Cost Variability	95.00%
Plus/Minus $120 million | Company's Share
Regulation and Rates [Line Items]
Annual Power Cost Variability	5.00%

Regulation_and_Rates_Details

Regulation and Rates (Details) (USD $)	12 Months Ended			7 Months Ended	11 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jan. 31, 2013	Dec. 31, 2013	Feb. 28, 2012	Nov. 09, 2009	Nov. 08, 2009	Dec. 22, 2009
						MW	MW	MW
Regulation and Rates [Line Items]
Public Utilities, Rate Case, Deferred Storm Costs Threshold	$8,000,000
Facility Power Capacity						343	273	229
Accrual for Environmental Loss Contingencies	25,200,000
Electric
Regulation and Rates [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Losses, Low Estimate	5,700,000
Environmental Expense and Liabilities	13,400,000	12,300,000	10,900,000
Gas plant
Regulation and Rates [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Losses, Low Estimate	35,400,000
Environmental Expense and Liabilities	52,600,000	45,100,000	66,400,000
PUGET SOUND ENERGY, INC.
Regulation and Rates [Line Items]
Regulatory Liabilities Reclassified from Accumulated Depreciation	313,100,000	269,500,000
Storm Damage Costs Incurred During Period	29,700,000	9,400,000
Storm Damage Costs Deferred During Period	18,000,000	0
American Recovery and Reinvestment Tax Act of 2009, Grant Approved Amount			205,300,000						28,700,000
American Recovery and Reinvestment Tax Act of 2009, Grant, Amortization Period Included in Customer Pass Through					11 months
American Recovery and Reinvestment Tax Act of 2009, Grant, Overall Average Rate Reduction	-0.26%				2.76%
American Recovery and Reinvestment Tax Act of 2009, Total Grant Pass Through Amount	58,500,000
American Recovery and Reinvestment Tax Act of 2009, Grant, Approved Pass Back Rate			0.1
American Recovery and Reinvestment Tax Act of 2009, Grant Amortization Period					10 years
American Recovery and Reinvestment Tax Act of 2009, Grant Pass Through Amount	37,800,000				34,600,000
American Recovery and Reinvestment Tax Act of 2009, Grant Pass Through Interest Amount	$20,600,000			$2,400,000	$23,800,000
Requlatory Assets Related to Power Contracts | Parent Company [Member]
Regulation and Rates [Line Items]
Net Regulatory Assets, Remaining Amortization Period, Min	1 year
Net Regulatory Assets, Remaining Amortization Period, Max	22 years
Chelan PUD contract initiation | PUGET SOUND ENERGY, INC.
Regulation and Rates [Line Items]
Net Regulatory Assets, Remaining Amortization Period	16 years 9 months 18 days
Snoqualmie | PUGET SOUND ENERGY, INC.
Regulation and Rates [Line Items]
Net Regulatory Assets, Remaining Amortization Period	3 years 9 months
PGA receivable [Domain] | PUGET SOUND ENERGY, INC.
Regulation and Rates [Line Items]
Net Regulatory Assets, Remaining Amortization Period	1 year
Electron Unrecovered Loss | PUGET SOUND ENERGY, INC.
Regulation and Rates [Line Items]
Net Regulatory Assets, Remaining Amortization Period	4 years
White River relicensing and other costs | PUGET SOUND ENERGY, INC.
Regulation and Rates [Line Items]
Net Regulatory Assets, Remaining Amortization Period	17 years 10 months 24 days
Baker Dam Licensing Operating Maintenance Costs [Member] | PUGET SOUND ENERGY, INC.
Regulation and Rates [Line Items]
Net Regulatory Assets, Remaining Amortization Period	44 years
Storm damage costs electric | PUGET SOUND ENERGY, INC.
Regulation and Rates [Line Items]
Net Regulatory Assets, Remaining Amortization Period, Min	1 year
Net Regulatory Assets, Remaining Amortization Period, Max	4 years
Colstrip common property | PUGET SOUND ENERGY, INC.
Regulation and Rates [Line Items]
Net Regulatory Assets, Remaining Amortization Period	9 years 6 months
Snoqualmie Licensing Operating Maintenance Costs | PUGET SOUND ENERGY, INC.
Regulation and Rates [Line Items]
Net Regulatory Assets, Remaining Amortization Period	30 years
Deferred Washington Commission AFUDC | PUGET SOUND ENERGY, INC.
Regulation and Rates [Line Items]
Net Regulatory Assets, Remaining Amortization Period, Max	35 years
Energy Conservation Costs [Member] | PUGET SOUND ENERGY, INC.
Regulation and Rates [Line Items]
Net Regulatory Assets, Remaining Amortization Period, Min	1 year
Net Regulatory Assets, Remaining Amortization Period, Max	2 years
Unamortized loss on reacquired debt | PUGET SOUND ENERGY, INC.
Regulation and Rates [Line Items]
Net Regulatory Assets, Remaining Amortization Period, Min	1 year
Net Regulatory Assets, Remaining Amortization Period, Max	21 years 6 months
Mint Farm ownership and operating costs | PUGET SOUND ENERGY, INC.
Regulation and Rates [Line Items]
Net Regulatory Assets, Remaining Amortization Period	10 years 3 months 18 days
Ferndale | PUGET SOUND ENERGY, INC.
Regulation and Rates [Line Items]
Net Regulatory Assets, Remaining Amortization Period	4 years 9 months 18 days
Investment in Bonneville Exchange power contract | PUGET SOUND ENERGY, INC.
Regulation and Rates [Line Items]
Net Regulatory Assets, Remaining Amortization Period	2 years 6 months
Lower Snake River | PUGET SOUND ENERGY, INC.
Regulation and Rates [Line Items]
Net Regulatory Assets, Remaining Amortization Period, Min	1 year 4 months
Net Regulatory Assets, Remaining Amortization Period, Max	22 years 4 months
Regulatory liabilities related to power contracts | Parent Company [Member]
Regulation and Rates [Line Items]
Net Regulatory Assets, Remaining Amortization Period, Min	1 year
Net Regulatory Assets, Remaining Amortization Period, Max	37 years
Renewable energy credits | PUGET SOUND ENERGY, INC.
Regulation and Rates [Line Items]
Net Regulatory Assets, Remaining Amortization Period	1 year
Deferred credit on Biogas sale | PUGET SOUND ENERGY, INC.
Regulation and Rates [Line Items]
Net Regulatory Assets, Remaining Amortization Period	1 year
Deferred credit on gas pipeline capacity | PUGET SOUND ENERGY, INC.
Regulation and Rates [Line Items]
Net Regulatory Assets, Remaining Amortization Period, Max	3 years 9 months 18 days
Decoupling over-collection | PUGET SOUND ENERGY, INC.
Regulation and Rates [Line Items]
Net Regulatory Assets, Remaining Amortization Period	2 years
Summit purchase option buy-out | PUGET SOUND ENERGY, INC.
Regulation and Rates [Line Items]
Net Regulatory Assets, Remaining Amortization Period	5 years 9 months 18 days
Treasury grants | PUGET SOUND ENERGY, INC.
Regulation and Rates [Line Items]
Net Regulatory Assets, Remaining Amortization Period, Min	5 years
Net Regulatory Assets, Remaining Amortization Period, Max	44 years
Decoupling over-collection [Domain] | PUGET SOUND ENERGY, INC.
Regulation and Rates [Line Items]
Net Regulatory Assets, Remaining Amortization Period	1 year
Various other regulatory liabilities | PUGET SOUND ENERGY, INC.
Regulation and Rates [Line Items]
Net Regulatory Assets, Remaining Amortization Period, Max	4 years
Maximum | Property tax tracker | PUGET SOUND ENERGY, INC.
Regulation and Rates [Line Items]
Net Regulatory Assets, Remaining Amortization Period	2 years
Maximum | Decoupling Under-Collection | PUGET SOUND ENERGY, INC.
Regulation and Rates [Line Items]
Net Regulatory Assets, Remaining Amortization Period	2 years
Maximum | Deferred gain on Jefferson County sale | PUGET SOUND ENERGY, INC.
Regulation and Rates [Line Items]
Net Regulatory Assets, Remaining Amortization Period	1 year

Dividend_Payment_Restrictions_

Dividend Payment Restrictions (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014
Parent [Line Items]
Retained Earnings, Unappropriated	$438.40
Dividends, Earnings Before Interest, Tax, Deprecation and Amortization Ratio, Threshold For Dividend Payment	2
Dividends, Earnings Before Interest, Tax, Deprecation and Amortization Ratio at Period End	3.1
PUGET SOUND ENERGY, INC.
Parent [Line Items]
Dividends, Common Equity Ratio, Threshold For Dividend Payment	44.00%
Dividends, Earnings Before Interest, Tax, Deprecation and Amortization Ratio, Threshold For Dividend Payment	3
Dividends, Common Equity Ratio at Period End	47.70%
Dividends, Earnings Before Interest, Tax, Deprecation and Amortization Ratio at Period End	4.3

Utility_Plant_Details

Utility Plant (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013
Public Utility, Property, Plant and Equipment
Accumulated amortization of capital leases	28,400,000		$20,800,000
Utility Plant
Distribution plant	4,748,988,000		4,448,451,000
Production plant	2,973,853,000		2,966,223,000
Transmission plant	1,189,296,000		1,043,605,000
General plant	481,116,000		504,965,000
Intangible plant (including capitalized software)	311,959,000		316,614,000
Plant acquisition adjustment	242,826,000		242,826,000
Underground storage	28,859,000		27,857,000
Liquefied natural gas storage	12,628,000		12,622,000
Plant held for future use	54,996,000		28,742,000
Recoverable cushion gas	8,655,000		8,655,000
Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment	91,519,000		124,589,000
Public Utilities, Property, Plant and Equipment Grant	-105,659,000		0
Capital leases, net of accumulated amortization	9,473,000	[1]	17,051,000	[1]
Less: Accumulated depreciation and amortization	-1,611,220,000		-1,373,178,000
Subtotal	8,437,289,000		8,369,022,000
Construction work in progress	239,690,000		310,318,000
Net utility plant	8,676,979,000		8,679,340,000
Minimum
Public Utility, Property, Plant and Equipment
Distribution plant, Estimated Useful Life	10 years
Production plant, Estimated Useful Life	25 years
Transmission plant, Estimated Useful Life	45 years
General plant, Estimated Useful Life	5 years
Intangible plant (including capitalized software), Estimated Useful Life	3 years
Plant acquisition adjustment, Estimated Useful Life	7 years
Underground storage, Estimated Useful Life	25 years
Liquefied natural gas storage, Estimated Useful Life	25 years
Public Utilities, Property, Plant and Equipment, Plant Not Classified, Estimated Useful Life	1 year
Capital leases, net of accumulated amortization, Estimated Useful Life	1 year	[1]
Maximum
Public Utility, Property, Plant and Equipment
Distribution plant, Estimated Useful Life	50 years
Production plant, Estimated Useful Life	125 years
Transmission plant, Estimated Useful Life	65 years
General plant, Estimated Useful Life	35 years
Intangible plant (including capitalized software), Estimated Useful Life	50 years
Plant acquisition adjustment, Estimated Useful Life	30 years
Underground storage, Estimated Useful Life	60 years
Liquefied natural gas storage, Estimated Useful Life	45 years
Public Utilities, Property, Plant and Equipment, Plant Not Classified, Estimated Useful Life	100 years
Capital leases, net of accumulated amortization, Estimated Useful Life	5 years	[1]
PUGET SOUND ENERGY, INC.
Public Utility, Property, Plant and Equipment
Accumulated amortization of capital leases	28,400,000		20,800,000
Utility Plant
Distribution plant	6,417,551,000		6,127,732,000
Production plant	3,907,224,000		3,948,270,000
Transmission plant	1,306,009,000		1,162,929,000
General plant	553,130,000		599,156,000
Intangible plant (including capitalized software)	304,135,000		309,972,000
Plant acquisition adjustment	282,792,000		282,792,000
Underground storage	42,494,000		41,501,000
Liquefied natural gas storage	14,498,000		14,492,000
Plant held for future use	55,148,000		28,895,000
Recoverable cushion gas	8,655,000		8,655,000
Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment	91,519,000		124,589,000
Public Utilities, Property, Plant and Equipment Grant	-105,659,000		0
Capital leases, net of accumulated amortization	9,473,000	[1]	17,051,000	[1]
Less: Accumulated depreciation and amortization	-4,449,680,000		-4,297,012,000
Subtotal	8,437,289,000		8,369,022,000
Construction work in progress	239,690,000		310,318,000
Net utility plant	8,676,979,000		$8,679,340,000
[1]	Accumulated amortization of capital leases at Puget Energy was $28.4 million in 2014 and $20.8 million in 2013. Accumulated amortization of capital leases at PSE was $28.4 million in 2014 and $20.8 million in 2013.

Utility_Plant_Jointly_Owned_Ut

Utility Plant - Jointly Owned Utility Plant (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Jointly Owned Utility Plant Interests
Asset Retirement Obligation, Liabilities Incurred	$0	$350
Colstrip Units 1 & 2
Jointly Owned Utility Plant Interests
Company’s Ownership Share	50.00%
Plant in Service at Cost	158,516
Accumulated Depreciation	-12,047
Colstrip Units 3 & 4
Jointly Owned Utility Plant Interests
Company’s Ownership Share	25.00%
Plant in Service at Cost	234,787
Accumulated Depreciation	-28,763
Colstrip Units 1 – 4 Common Facilities
Jointly Owned Utility Plant Interests
Plant in Service at Cost	83
Accumulated Depreciation	-21
Frederickson 1
Jointly Owned Utility Plant Interests
Company’s Ownership Share	49.85%
Plant in Service at Cost	61,771
Accumulated Depreciation	-5,750
Jackson Prairie [Member]
Jointly Owned Utility Plant Interests
Company’s Ownership Share	33.34%
Plant in Service at Cost	28,185
Accumulated Depreciation	-4,099
PUGET SOUND ENERGY, INC. | Colstrip Units 1 & 2
Jointly Owned Utility Plant Interests
Plant in Service at Cost	293,103
Accumulated Depreciation	-146,635
PUGET SOUND ENERGY, INC. | Colstrip Units 3 & 4
Jointly Owned Utility Plant Interests
Plant in Service at Cost	509,619
Accumulated Depreciation	-303,594
PUGET SOUND ENERGY, INC. | Colstrip Units 1 – 4 Common Facilities
Jointly Owned Utility Plant Interests
Plant in Service at Cost	252
Accumulated Depreciation	-189
PUGET SOUND ENERGY, INC. | Frederickson 1
Jointly Owned Utility Plant Interests
Plant in Service at Cost	70,719
Accumulated Depreciation	-14,698
PUGET SOUND ENERGY, INC. | Jackson Prairie [Member]
Jointly Owned Utility Plant Interests
Plant in Service at Cost	42,494
Accumulated Depreciation	($18,409)

Utility_Plant_Asset_Retirement

Utility Plant - Asset Retirement Obligation (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset retirement obligation at beginning of period	$48,687	$45,496
New asset retirement obligation recognized in the period	0	350
Liability settled in the period	-602	-1,188
Revisions in estimated cash flows	-480	2,769
Accretion expense	1,304	1,260
Asset retirement obligation at end of period	$48,909	$48,687

LongTerm_Debt_Schedule_of_Long

Long-Term Debt (Schedule of Long-Term Debt Instruments) (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013		Jun. 29, 2014	Feb. 28, 2009	23-May-13
In Thousands, unless otherwise specified
Debt Instrument [Line Items]
Total PSE long-term debt	$5,462,272
Long Term Debt, Reconciliation, Fair Value Adjustment	-218,619		-229,746
Net PSE long-term debt	5,243,608		5,232,476
Senior secured credit facility
Debt Instrument [Line Items]
Total PSE long-term debt	0		299,000
Term Loan
Debt Instrument [Line Items]
Total PSE long-term debt					299,000	1,225,000
Term Loan | Term Loan series due 2017 [Member]
Debt Instrument [Line Items]
Total PSE long-term debt	100,000		0
Term Loan | Term Loan series due 2016 [Member]
Debt Instrument [Line Items]
Total PSE long-term debt	99,000		0
Term Loan | Term Loan
Debt Instrument [Line Items]
Total PSE long-term debt	100,000		0
Senior Secured Note
Debt Instrument [Line Items]
Unamortized discount on senior notes	-32		-36
Senior Secured Note | 6.500% Senior Secured Note Due 2020
Debt Instrument [Line Items]
Stated interest rate percent	6.50%
Total PSE long-term debt	450,000		450,000
Senior Secured Note | 6.000% Senior Secured Note Due 2021
Debt Instrument [Line Items]
Stated interest rate percent	6.00%
Total PSE long-term debt	500,000		500,000
Senior Secured Note | 5.625% Senior Secured Note Due 2022
Debt Instrument [Line Items]
Total PSE long-term debt	450,000		450,000
PUGET SOUND ENERGY, INC.
Debt Instrument [Line Items]
Total PSE long-term debt	3,763,272
Unamortized discount on senior notes	-13		-14
Net PSE long-term debt	3,763,259		3,763,258
PUGET SOUND ENERGY, INC. | Senior Notes and First Mortgage Bonds | 7.350% Series Due 2015
Debt Instrument [Line Items]
Stated interest rate percent	7.35%
Total PSE long-term debt	10,000		10,000
PUGET SOUND ENERGY, INC. | Senior Notes and First Mortgage Bonds | 7.360% Series Due 2015
Debt Instrument [Line Items]
Stated interest rate percent	7.36%
Total PSE long-term debt	2,000		2,000
PUGET SOUND ENERGY, INC. | Senior Notes and First Mortgage Bonds | 5.197% Series Due 2015
Debt Instrument [Line Items]
Stated interest rate percent	5.20%
Total PSE long-term debt	150,000		150,000
PUGET SOUND ENERGY, INC. | Senior Notes and First Mortgage Bonds | 6.750% Series Due 2016
Debt Instrument [Line Items]
Stated interest rate percent	6.75%
Total PSE long-term debt	250,000		250,000
PUGET SOUND ENERGY, INC. | Senior Notes and First Mortgage Bonds | 5.500% Secured Promissory Note Due 2017
Debt Instrument [Line Items]
Stated interest rate percent	5.50%
Total PSE long-term debt	2,412	[1]	2,412	[1]
PUGET SOUND ENERGY, INC. | Senior Notes and First Mortgage Bonds | 6.740% Series Due 2018
Debt Instrument [Line Items]
Stated interest rate percent	6.74%
Total PSE long-term debt	200,000		200,000
PUGET SOUND ENERGY, INC. | Senior Notes and First Mortgage Bonds | 7.150% Series Due 2025
Debt Instrument [Line Items]
Stated interest rate percent	7.15%
Total PSE long-term debt	15,000		15,000
PUGET SOUND ENERGY, INC. | Senior Notes and First Mortgage Bonds | 7.200% Series Due 2025
Debt Instrument [Line Items]
Stated interest rate percent	7.20%
Total PSE long-term debt	2,000		2,000
PUGET SOUND ENERGY, INC. | Senior Notes and First Mortgage Bonds | 7.020% Series Due 2027
Debt Instrument [Line Items]
Stated interest rate percent	7.02%
Total PSE long-term debt	300,000		300,000
PUGET SOUND ENERGY, INC. | Senior Notes and First Mortgage Bonds | 7.000% Series Due 2029
Debt Instrument [Line Items]
Stated interest rate percent	7.00%
Total PSE long-term debt	100,000		100,000
PUGET SOUND ENERGY, INC. | Senior Notes and First Mortgage Bonds | 3.900% Series Due 2031
Debt Instrument [Line Items]
Total PSE long-term debt	138,460		138,460
PUGET SOUND ENERGY, INC. | Senior Notes and First Mortgage Bonds | 5.483% Series Due 2035
Debt Instrument [Line Items]
Stated interest rate percent	5.48%
Total PSE long-term debt	250,000		250,000
PUGET SOUND ENERGY, INC. | Senior Notes and First Mortgage Bonds | 6.724% Series Due 2036
Debt Instrument [Line Items]
Stated interest rate percent	6.72%
Total PSE long-term debt	250,000		250,000
PUGET SOUND ENERGY, INC. | Senior Notes and First Mortgage Bonds | 6.274% Series Due 2037
Debt Instrument [Line Items]
Stated interest rate percent	6.27%
Total PSE long-term debt	300,000		300,000
PUGET SOUND ENERGY, INC. | Senior Notes and First Mortgage Bonds | 5.757% Series Due 2039
Debt Instrument [Line Items]
Stated interest rate percent	5.76%
Total PSE long-term debt	350,000		350,000
PUGET SOUND ENERGY, INC. | Senior Notes and First Mortgage Bonds | 5.795% Series Due 2040
Debt Instrument [Line Items]
Stated interest rate percent	5.80%
Total PSE long-term debt	325,000		325,000
PUGET SOUND ENERGY, INC. | Senior Notes and First Mortgage Bonds | 5.764% Series Due 2040
Debt Instrument [Line Items]
Stated interest rate percent	5.76%
Total PSE long-term debt	250,000		250,000
PUGET SOUND ENERGY, INC. | Senior Notes and First Mortgage Bonds | 4.434% Series Due 2041
Debt Instrument [Line Items]
Stated interest rate percent	4.43%
Total PSE long-term debt	250,000		250,000
PUGET SOUND ENERGY, INC. | Senior Notes and First Mortgage Bonds | 5.638% Series Due 2041
Debt Instrument [Line Items]
Stated interest rate percent	5.64%
Total PSE long-term debt	300,000		300,000
PUGET SOUND ENERGY, INC. | Senior Notes and First Mortgage Bonds | 4.700% Series Due 2051
Debt Instrument [Line Items]
Stated interest rate percent	4.70%
Total PSE long-term debt	45,000		45,000
PUGET SOUND ENERGY, INC. | Pollution Control Bonds
Debt Instrument [Line Items]
Total PSE long-term debt							161,900
PUGET SOUND ENERGY, INC. | Pollution Control Bonds | 3.900% Series Due 2031
Debt Instrument [Line Items]
Stated interest rate percent	3.90%
PUGET SOUND ENERGY, INC. | Pollution Control Bonds | 4.000% Series Due 2031
Debt Instrument [Line Items]
Stated interest rate percent	4.00%
Total PSE long-term debt	23,400		23,400
PUGET SOUND ENERGY, INC. | Junior Subordinated Notes | 6.974% Series Due 2067
Debt Instrument [Line Items]
Stated interest rate percent	6.97%
Total PSE long-term debt	$250,000		$250,000
PUGET SOUND ENERGY, INC. | Junior Subordinated Notes | 6.500% Senior Secured Note Due 2020
Debt Instrument [Line Items]
Stated interest rate percent	6.50%
PUGET SOUND ENERGY, INC. | Junior Subordinated Notes | 6.000% Senior Secured Note Due 2021
Debt Instrument [Line Items]
Stated interest rate percent	6.00%
PUGET SOUND ENERGY, INC. | Junior Subordinated Notes | 5.625% Senior Secured Note Due 2022
Debt Instrument [Line Items]
Stated interest rate percent	5.63%
[1]	Accumulated amortization of capital leases at Puget Energy was $28.4 million in 2014 and $20.8 million in 2013. Accumulated amortization of capital leases at PSE was $28.4 million in 2014 and $20.8 million in 2013.

LongTerm_Debt_Narrative_Detail

Long-Term Debt (Narrative) (Details) (USD $)	0 Months Ended	3 Months Ended	0 Months Ended	12 Months Ended
	Feb. 10, 2012	Jun. 30, 2014	Dec. 06, 2010	Dec. 31, 2014	Dec. 31, 2013	Feb. 28, 2009	Jun. 29, 2014	23-May-13
Debt Instrument [Line Items]
Long-term debt				$5,462,272,000
Debt Instrument, Term	5 years	3 years
Current borrowing capacity of line of credit	1,000,000,000
Maximum borrowing capacity				1,300,000,000
Senior secured credit facility
Debt Instrument [Line Items]
Long-term debt				0	299,000,000
Debt Instrument, Term			5 years
Capital Expenditure Facility
Debt Instrument [Line Items]
Current borrowing capacity of line of credit						1,000,000,000
Term Loan
Debt Instrument [Line Items]
Long-term debt						1,225,000,000	299,000,000
Debt Instrument, Term		2 years	5 years
Revolving Credit Facility
Debt Instrument [Line Items]
Current borrowing capacity of line of credit	800,000,000
PUGET SOUND ENERGY, INC.
Debt Instrument [Line Items]
Long-term debt				3,763,272,000
Current borrowing capacity of line of credit				1,000,000,000
Maximum borrowing capacity				1,450,000,000
PUGET SOUND ENERGY, INC. | Pollution Control Bonds
Debt Instrument [Line Items]
Long-term debt								161,900,000
PUGET SOUND ENERGY, INC. | Pollution Control Bonds | 5.010% Series Due 2031
Debt Instrument [Line Items]
Stated interest rate percent								5.01%
PUGET SOUND ENERGY, INC. | Pollution Control Bonds | 3.910% Series Due 2031
Debt Instrument [Line Items]
Stated interest rate percent								3.91%
Puget Energy | Pollution Control Bonds
Debt Instrument [Line Items]
Liabilities and Equity, Fair Value Adjustment				$18,000,000

LongTerm_Debt_Schedule_of_Matu

Long-Term Debt (Schedule of Maturities of Long-Term Debt) (Details) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Maturities of Long-term Debt [Abstract]
2014	$162,000
2015	449,000
2016	102,412
2017	200,000
2018	0
Thereafter	4,548,860
Total long-term debt	5,462,272
PUGET SOUND ENERGY, INC.
Maturities of Long-term Debt [Abstract]
2014	162,000
2015	250,000
2016	2,412
2017	200,000
2018	0
Thereafter	3,148,860
Total long-term debt	3,763,272
PUGET ENERGY
Maturities of Long-term Debt [Abstract]
2014	0
2015	199,000
2016	100,000
2017	0
2018	0
Thereafter	1,400,000
Total long-term debt	$1,699,000

Liquidity_Facilities_and_Other1

Liquidity Facilities and Other Financing Arrangements (Details) (USD $)	0 Months Ended	12 Months Ended
	Feb. 10, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Short-term Debt [Line Items]
Short-term debt		85,000,000	$162,000,000
Current borrowing capacity of line of credit	1,000,000,000
Maximum borrowing capacity		1,300,000,000
Energy Hedging Activities [Member]
Short-term Debt [Line Items]
Current borrowing capacity of line of credit		350,000,000
Senior secured credit facility
Short-term Debt [Line Items]
Short-term debt		0		0
Revolving Credit Facility
Short-term Debt [Line Items]
Current borrowing capacity of line of credit	800,000,000
Basis spread on variable rate (percent)		1.75%
Commitment fee percentage for line of credit	0.28%
PUGET SOUND ENERGY, INC.
Short-term Debt [Line Items]
Short-term debt		85,000,000	162,000,000	162,000,000
Weighted-average interest rate on short-term debt (percent)		4.05%		3.93%
Current borrowing capacity of line of credit		1,000,000,000
Current same-day borrowing capacity		75,000,000
Maximum borrowing capacity		1,450,000,000
Maximum capitalization percentage		65.00%
Derivative, Basis Spread on Variable Rate		1.25%
Line of Credit, Unused Capacity, Commitment Fee Percentage		0.18%
PUGET SOUND ENERGY, INC. | Promissory Note with Puget Energy
Short-term Debt [Line Items]
Outstanding amount for line of credit		28,900,000
PUGET SOUND ENERGY, INC. | Working Capital Needs
Short-term Debt [Line Items]
Current borrowing capacity of line of credit		650,000,000
PUGET SOUND ENERGY, INC. | Energy Hedging Activities [Member]
Short-term Debt [Line Items]
Outstanding amount for line of credit		1,000,000
Current borrowing capacity of line of credit		350,000,000
PUGET SOUND ENERGY, INC. | Letter of Credit | Working Capital Needs
Short-term Debt [Line Items]
Outstanding amount for line of credit		85,000,000
Current borrowing capacity of line of credit		4,200,000
PUGET SOUND ENERGY, INC. | Senior secured credit facility | Promissory Note with Puget Energy
Short-term Debt [Line Items]
Current borrowing capacity of line of credit		30,000,000
Basis spread on variable rate (percent)		0.25%
Debt instrument variable rate basis		one-month LIBOR

Leases_Schedule_of_Operating_L

Leases (Schedule of Operating Lease Expense) (Details) (PUGET SOUND ENERGY, INC., USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
PUGET SOUND ENERGY, INC.
Operating Leases, Rent Expense, Net [Abstract]
Operating lease expense net of sublease receipts	$30,737	$29,392	$29,661

Leases_Schedule_of_Future_Mini

Leases (Schedule of Future Minimum Lease Payments for Non-cancellable Leases) (Details) (PUGET SOUND ENERGY, INC., USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
PUGET SOUND ENERGY, INC.
Operating
2014	$17,677
2015	21,454
2016	22,179
2017	20,423
2018	15,180
Thereafter	120,791
Total minimum lease payments	217,704
Capital
2014	8,160
2015	2,178
2016	0
2017	0
2018	0
Thereafter	0
Total minimum lease payments	$10,338

Accounting_for_Derivative_Inst2

Accounting for Derivative Instruments and Hedging Activities (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014
Derivative [Line Items]
Expected losses reclassified to OCI related to cash flow hedges within twelve months	$500,000
Electric Portfolio
Derivative [Line Items]
Collateral Already Posted, Aggregate Fair Value	0
PUGET SOUND ENERGY, INC.
Derivative [Line Items]
Expected losses reclassified to OCI related to cash flow hedges within twelve months	1,100,000
PUGET ENERGY | Interest Rate Swap
Derivative [Line Items]
Number of interest rate derivatives held	0
Credit Rating | Electric Portfolio
Derivative [Line Items]
Collateral Already Posted, Aggregate Fair Value	0	[1]
Credit Rating | Natural Gas Portfolio
Derivative [Line Items]
Collateral Already Posted, Aggregate Fair Value	$1,000,000
External Credit Rating, Investment Grade [Member] | Electric Portfolio
Derivative [Line Items]
Percentage of derivatives with credit risk exposure	99.30%
External Credit Rating, Non Investment Grade [Member] | Electric Portfolio
Derivative [Line Items]
Percentage of derivatives with credit risk exposure	0.70%
[1]	Failure by PSE to maintain an investment grade credit rating from each of the major credit rating agencies provides counterparties a contractual right to demand collateral.

Accounting_for_Derivative_Inst3

Accounting for Derivative Instruments and Hedging Activities (Schedule of Derivative Assets and Liabilities) (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013
Derivative [Line Items]
Assets, Current	$21,178,000		$18,867,000
Assets, Long-term	3,170,000		7,733,000
Liabilities, Current	142,195,000		48,049,000
Liabilities, Long-term	62,913,000		38,162,000
PUGET ENERGY
Derivative [Line Items]
Liabilities, Current	6,222,000		6,584,000
Liabilities, Long-term	2,850,000		6,656,000
PUGET SOUND ENERGY, INC.
Derivative [Line Items]
Assets, Current	21,178,000		18,867,000
Assets, Long-term	3,170,000		7,733,000
Liabilities, Current	135,973,000		41,465,000
Liabilities, Long-term	60,063,000		31,523,000
Interest Rate Swap | PUGET ENERGY
Derivative [Line Items]
Number of interest rate derivatives held	0
Commodity Contract
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	24,348,000	[1]	26,600,000	[1]
Total derivative assets	24,348,000		26,600,000
Total derivative liabilities	196,035,000		72,988,000
Derivative Asset, Collateral, Obligation to Return Cash, Offset	0		0
Derivative, Collateral, Obligation to Return Securities	-23,066,000		-19,491,000
Derivative, Collateral, Obligation to Return Cash	0		0
Derivative Asset, Fair Value, Amount Offset Against Collateral	1,282,000		7,109,000
Derivative Liability, Fair Value, Gross Liability	196,035,000	[1]	72,988,000	[1]
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	0	[2]	0
Derivative, Collateral, Right to Reclaim Securities	-23,066,000		-19,491,000
Derivative, Collateral, Right to Reclaim Cash	-20,000		0
Derivative Liability, Fair Value, Amount Offset Against Collateral	172,949,000		53,497,000
Natural Gas Portfolio
Derivative [Line Items]
Offsetting regulatory assets	69,300,000		27,600,000
Interest Rate Contract
Derivative [Line Items]
Total derivative liabilities	9,073,000	[2]	13,223,000	[2]
Derivative Liability, Fair Value, Gross Liability	9,073,000	[1],[2]	13,223,000	[1],[2]
Derivative Liability, Collateral, Right to Reclaim Cash, Offset			0	[2]
Derivative, Collateral, Right to Reclaim Securities	0	[2]	0	[2]
Derivative, Collateral, Right to Reclaim Cash	0	[2]	0	[2]
Derivative Liability, Fair Value, Amount Offset Against Collateral	9,073,000	[2]	13,223,000	[2]
Not Designated as Hedging Instrument
Derivative [Line Items]
Total derivative assets	24,348,000	[3]	26,600,000	[3]
Total derivative liabilities	205,108,000	[4]	86,211,000	[4]
Not Designated as Hedging Instrument | PUGET ENERGY
Derivative [Line Items]
Assets, Current	21,178,000	[3]	18,867,000	[3]
Assets, Long-term	3,170,000	[3]	7,733,000	[3]
Liabilities, Current	142,195,000	[4]	48,049,000	[4]
Liabilities, Long-term	62,913,000	[4]	38,162,000	[4]
Not Designated as Hedging Instrument | Interest Rate Swap
Derivative [Line Items]
Derivative, Notional Amount	450,000,000	[5]	450,000,000	[5]
Total derivative assets	0	[3],[5]	0	[3],[5]
Total derivative liabilities	9,073,000	[4],[5]	13,223,000	[4],[5]
Not Designated as Hedging Instrument | Electric Generation Fuel
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	140,200,000		145,600,000
Not Designated as Hedging Instrument | Purchased Electricity
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	5,400,000		8,600,000
Not Designated as Hedging Instrument | Electric Portfolio
Derivative [Line Items]
Total derivative assets	4,822,000	[3]	18,479,000	[3]
Total derivative liabilities	107,228,000	[4]	37,312,000	[4]
Not Designated as Hedging Instrument | Natural Gas Portfolio
Derivative [Line Items]
Total derivative assets	19,526,000	[3],[6]	8,121,000	[3],[6]
Total derivative liabilities	$88,807,000	[4],[6]	$35,676,000	[4],[6]
Not Designated as Hedging Instrument | Gas Derivatives
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	360,400,000	[6]	423,500,000	[6]
[1]	All Derivative Contract deals are executed under ISDA, NAESB and WSPP Master Netting Agreements with Right of Offset.
[2]	Interest Rate Swap Contracts are only held at Puget Energy.
[3]	Balance sheet location: Current and Long-term Unrealized gain on derivative instruments.
[4]	Balance sheet location: Current and Long-term Unrealized loss on derivative instruments.
[5]	Interest rate swap contracts are only held at Puget Energy.
[6]	PSE had a net derivative liability and an offsetting regulatory asset of $69.3 million at December 31, 2014 and $27.6 million at December 31, 2013 related to contracts used to economically hedge the cost of physical gas purchased to serve natural gas customers. All fair value adjustments on derivatives relating to the natural gas business have been deferred in accordance with ASC 980, due to the PGA mechanism.

Accounting_for_Derivative_Inst4

Accounting for Derivative Instruments and Hedging Activities (Schedule of Amounts Recognized in Statement of Income) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Derivative Instruments, (Loss) Gain [Line Items]
Unrealized (gain) loss on derivative instruments	$84,146		($102,744)		($133,606)
PUGET SOUND ENERGY, INC.
Derivative Instruments, (Loss) Gain [Line Items]
Unrealized (gain) loss on derivative instruments	85,636		-98,880		-119,120
Not Designated as Hedging Instrument | Interest Rate Contract | Other Income (Deductions)
Derivative Instruments, (Loss) Gain [Line Items]
Unrealized (gain) loss on derivative instruments	3,915		-2,420		4,288
Not Designated as Hedging Instrument | Interest Rate Contract | Interest Expense
Derivative Instruments, (Loss) Gain [Line Items]
Unrealized (gain) loss on derivative instruments	-500		5,904		29,727
Not Designated as Hedging Instrument | Commodity Contract | Unrealized (Gain) Loss on Derivative Instruments, Net
Derivative Instruments, (Loss) Gain [Line Items]
Unrealized (gain) loss on derivative instruments	84,146	[1]	-102,744	[1]	-131,407	[1]
Not Designated as Hedging Instrument | Commodity Contract | Electric Generation Fuel
Derivative Instruments, (Loss) Gain [Line Items]
Unrealized (gain) loss on derivative instruments	-6,511		27,008		66,762
Not Designated as Hedging Instrument | Commodity Contract | Purchased Electricity
Derivative Instruments, (Loss) Gain [Line Items]
Unrealized (gain) loss on derivative instruments	4,212		38,299		138,551
Not Designated as Hedging Instrument | PUGET ENERGY
Derivative Instruments, (Loss) Gain [Line Items]
Unrealized (gain) loss on derivative instruments	85,262		-33,953		107,921
Not Designated as Hedging Instrument | PUGET SOUND ENERGY, INC.
Derivative Instruments, (Loss) Gain [Line Items]
Unrealized (gain) loss on derivative instruments	83,337		-33,573		86,193
Not Designated as Hedging Instrument | PUGET SOUND ENERGY, INC. | Commodity Contract | Unrealized (Gain) Loss on Derivative Instruments, Net
Derivative Instruments, (Loss) Gain [Line Items]
Unrealized (gain) loss on derivative instruments	85,636		-98,880		-119,120
Not Designated as Hedging Instrument | PUGET SOUND ENERGY, INC. | Commodity Contract | Electric Generation Fuel
Derivative Instruments, (Loss) Gain [Line Items]
Unrealized (gain) loss on derivative instruments	-6,511		27,008		66,762
Not Designated as Hedging Instrument | PUGET SOUND ENERGY, INC. | Commodity Contract | Purchased Electricity
Derivative Instruments, (Loss) Gain [Line Items]
Unrealized (gain) loss on derivative instruments	$4,212		$38,299		$138,551
[1]	For 2012, the amount differs from the amount stated in the statement of income as it does not include amortization related to contracts that were recorded at fair value at the time of the February 2009 merger and subsequently designated as NPNS of $2.2 million for the year ended December 31, 2012.

Accounting_for_Derivative_Inst5

Accounting for Derivative Instruments and Hedging Activities (Schedule of Amounts Recognized in Other Comprehensive Income) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	($500,000)
PUGET SOUND ENERGY, INC.
Derivative Instruments, Gain (Loss) [Line Items]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	-1,100,000
Cash Flow Hedging | PUGET ENERGY
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	-716,000	-4,562,000	-18,382,000
Cash Flow Hedging | PUGET SOUND ENERGY, INC.
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	-2,551,000	-4,410,000	-13,346,000
Reclassification out of Accumulated Other Comprehensive Income | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] | PUGET ENERGY | Energy Related Derivative
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)		-57,000	-671,000
Reclassification out of Accumulated Other Comprehensive Income | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] | PUGET SOUND ENERGY, INC. | Interest Rate Contract
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)		-488,000	-488,000
Electric Generation Fuel | Cash Flow Hedging | PUGET ENERGY
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	0	0	100,000
Electric Generation Fuel | Cash Flow Hedging | PUGET SOUND ENERGY, INC.
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	0	0	97,000
Purchased Electricity | Reclassification out of Accumulated Other Comprehensive Income | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] | Cash Flow Hedging | PUGET SOUND ENERGY, INC.
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)		-3,922,000	-12,955,000
Electric Derivative [Member] | Electric Generation Fuel
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	0	0	100,000
Electric Derivative [Member] | Electric Generation Fuel | PUGET SOUND ENERGY, INC.
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	0	0	97,000
Electric Derivative [Member] | Purchased Electricity
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	-572,000
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	-572,000	-57,000	-671,000
Interest Rate Contract | Interest Expense
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	-144,000	-4,505,000	-17,811,000
Interest Rate Contract | Interest Expense | PUGET SOUND ENERGY, INC.
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	($488,000)

Accounting_for_Derivative_Inst6

Accounting for Derivative Instruments and Hedging Activities (Schedule of Effects of Non-hedging Derivative Instruments on Income) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Total gain (loss) recognized in income on derivatives	($84,146,000)		$102,744,000		$133,606,000
Derivative contracts classified as financing activities due to merger	-16,349,000		-34,250,000		-92,681,000
Other Comprehensive Income Reclassification Of Net Unrealized Gain Loss On Interest Rate Swaps During Period Net Of Tax	94,000		2,928,000		11,577,000
Not Designated as Hedging Instrument | Interest Rate Contract | Other Deductions
Derivative Instruments, Gain (Loss) [Line Items]
Total gain (loss) recognized in income on derivatives	-3,915,000		2,420,000		-4,288,000
Not Designated as Hedging Instrument | Interest Rate Contract | Interest Expense
Derivative Instruments, Gain (Loss) [Line Items]
Total gain (loss) recognized in income on derivatives	500,000		-5,904,000		-29,727,000
Not Designated as Hedging Instrument | Commodity contracts: | Unrealized (Gain) Loss on Derivative Instruments, Net
Derivative Instruments, Gain (Loss) [Line Items]
Total gain (loss) recognized in income on derivatives	-84,146,000	[1]	102,744,000	[1]	131,407,000	[1]
Not Designated as Hedging Instrument | Commodity contracts: | Electric Generation Fuel
Derivative Instruments, Gain (Loss) [Line Items]
Total gain (loss) recognized in income on derivatives	6,511,000		-27,008,000		-66,762,000
Not Designated as Hedging Instrument | Commodity contracts: | Purchased Electricity
Derivative Instruments, Gain (Loss) [Line Items]
Total gain (loss) recognized in income on derivatives	-4,212,000		-38,299,000		-138,551,000
Parent Company [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Amount Not Designated as Normal Purchase, Normal Sale					-2,200,000
Parent Company [Member] | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Total gain (loss) recognized in income on derivatives	-85,262,000		33,953,000		-107,921,000
PUGET SOUND ENERGY, INC.
Derivative Instruments, Gain (Loss) [Line Items]
Total gain (loss) recognized in income on derivatives	-85,636,000		98,880,000		119,120,000
PUGET SOUND ENERGY, INC. | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Total gain (loss) recognized in income on derivatives	-83,337,000		33,573,000		-86,193,000
PUGET SOUND ENERGY, INC. | Not Designated as Hedging Instrument | Commodity contracts: | Unrealized (Gain) Loss on Derivative Instruments, Net
Derivative Instruments, Gain (Loss) [Line Items]
Total gain (loss) recognized in income on derivatives	-85,636,000		98,880,000		119,120,000
PUGET SOUND ENERGY, INC. | Not Designated as Hedging Instrument | Commodity contracts: | Electric Generation Fuel
Derivative Instruments, Gain (Loss) [Line Items]
Total gain (loss) recognized in income on derivatives	6,511,000		-27,008,000		-66,762,000
PUGET SOUND ENERGY, INC. | Not Designated as Hedging Instrument | Commodity contracts: | Purchased Electricity
Derivative Instruments, Gain (Loss) [Line Items]
Total gain (loss) recognized in income on derivatives	($4,212,000)		($38,299,000)		($138,551,000)
[1]	For 2012, the amount differs from the amount stated in the statement of income as it does not include amortization related to contracts that were recorded at fair value at the time of the February 2009 merger and subsequently designated as NPNS of $2.2 million for the year ended December 31, 2012.

Accounting_for_Derivative_Inst7

Accounting for Derivative Instruments and Hedging Activities (Schedule of Contractual Contingent Liability Positions) (Details) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Electric Portfolio
Derivative [Line Items]
Fair Value Liability	($106,356)	[1]
Collateral Already Posted, Aggregate Fair Value	0
Contingent Collateral	37,398
Credit Rating | Electric Portfolio
Derivative [Line Items]
Fair Value Liability	-37,398	[1],[2]
Collateral Already Posted, Aggregate Fair Value	0	[2]
Contingent Collateral	37,398	[2]
Credit Rating | Natural Gas Portfolio
Derivative [Line Items]
Collateral Already Posted, Aggregate Fair Value	1,000
Requested Credit for Adequate Assurance | Electric Portfolio
Derivative [Line Items]
Fair Value Liability	-66,468	[1]
Collateral Already Posted, Aggregate Fair Value	0
Contingent Collateral	0
Forward Value of Contract | Electric Portfolio
Derivative [Line Items]
Fair Value Liability	-2,490	[1],[3]
Collateral Already Posted, Aggregate Fair Value	0	[3]
Contingent Collateral	$0	[3]
[1]	Represents the derivative fair value of contracts with contingent features for counterparties in net derivative liability positions. Excludes NPNS, accounts payable and accounts receivable.
[2]	Failure by PSE to maintain an investment grade credit rating from each of the major credit rating agencies provides counterparties a contractual right to demand collateral.
[3]	Collateral requirements may vary, based on changes in the forward value of underlying transactions relative to contractually defined collateral thresholds.

Fair_Value_Measurements_Assets

Fair Value Measurements - Assets and Liabilities Measured on Recurring Basis (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013
In Thousands, unless otherwise specified
Interest Rate Contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liabilities	$9,073	[1]	$13,223	[1]
Commodity Contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	24,348		26,600
Derivative Liabilities	196,035		72,988
Fair Value, Measurements, Recurring | PUGET ENERGY | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liabilities	9,073		13,223
Fair Value, Measurements, Recurring | PUGET ENERGY | Level 2 | Interest Rate Contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liabilities	9,073		13,223
Fair Value, Measurements, Recurring | PUGET ENERGY | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liabilities	0		0
Fair Value, Measurements, Recurring | PUGET ENERGY | Level 3 | Interest Rate Contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liabilities	0		0
Fair Value, Measurements, Recurring | PUGET ENERGY | Level 3 | Commodity Contract | Electric Portfolio
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	3,168	[2]
Derivative Liabilities	15,230	[2]
Fair Value, Measurements, Recurring | PUGET ENERGY | Level 3 | Commodity Contract | Natural Gas Portfolio
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	1,462	[2]
Derivative Liabilities	3,502	[2]
Fair Value, Measurements, Recurring | PUGET ENERGY | Total
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liabilities	9,073		13,223
Fair Value, Measurements, Recurring | PUGET ENERGY | Total | Interest Rate Contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liabilities	9,073		13,223
Fair Value, Measurements, Recurring | PUGET SOUND ENERGY, INC. | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	19,718		20,109
Derivative Liabilities	177,303		50,715
Fair Value, Measurements, Recurring | PUGET SOUND ENERGY, INC. | Level 2 | Commodity Contract | Electric Portfolio
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	1,654		14,661
Derivative Liabilities	91,998		18,073
Fair Value, Measurements, Recurring | PUGET SOUND ENERGY, INC. | Level 2 | Commodity Contract | Natural Gas Portfolio
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	18,064		5,448
Derivative Liabilities	85,305		32,642
Fair Value, Measurements, Recurring | PUGET SOUND ENERGY, INC. | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	4,630		6,491
Derivative Liabilities	18,732		22,273
Fair Value, Measurements, Recurring | PUGET SOUND ENERGY, INC. | Level 3 | Commodity Contract | Electric Portfolio
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets			3,818
Derivative Liabilities			19,239
Fair Value, Measurements, Recurring | PUGET SOUND ENERGY, INC. | Level 3 | Commodity Contract | Natural Gas Portfolio
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets			2,673
Derivative Liabilities			3,034
Fair Value, Measurements, Recurring | PUGET SOUND ENERGY, INC. | Total
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	24,348		26,600
Derivative Liabilities	196,035		72,988
Fair Value, Measurements, Recurring | PUGET SOUND ENERGY, INC. | Total | Commodity Contract | Electric Portfolio
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	4,822		18,479
Derivative Liabilities	107,228		37,312
Fair Value, Measurements, Recurring | PUGET SOUND ENERGY, INC. | Total | Commodity Contract | Natural Gas Portfolio
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	19,526		8,121
Derivative Liabilities	88,807		35,676
Carrying Amount | PUGET ENERGY
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents	37,527		44,302
Restricted Cash	32,863		7,171
Notes receivable and other	53,503		53,449
Total assets	123,893		104,922
Short Term Debt	85,000		162,000
Total liabilities	85,000		162,000
Carrying Amount | PUGET ENERGY | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents	37,527		44,302
Restricted Cash	32,863		7,171
Notes receivable and other	0		0
Total assets	70,390		51,473
Short Term Debt	85,000		162,000
Total liabilities	85,000		162,000
Carrying Amount | PUGET ENERGY | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents	0		0
Restricted Cash	0		0
Notes receivable and other	53,503		53,449
Total assets	53,503		53,449
Short Term Debt	0		0
Total liabilities	0		0
Carrying Amount | PUGET SOUND ENERGY, INC. | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents	37,466		44,111
Restricted Cash	32,863		7,171
Notes receivable and other	0		0
Total assets	70,329		51,282
Short Term Debt	85,000		162,000
Short-term debt owed by PSE to Puget Energy	0		0
Total liabilities	85,000		162,000
Carrying Amount | PUGET SOUND ENERGY, INC. | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents	0		0
Restricted Cash	0		0
Notes receivable and other	53,503		53,449
Total assets	53,503		53,449
Short Term Debt	0		0
Short-term debt owed by PSE to Puget Energy	28,933		29,598
Total liabilities	28,933		29,598
Carrying Amount | PUGET SOUND ENERGY, INC. | Total
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents	37,466		44,111
Restricted Cash	32,863		7,171
Notes receivable and other	53,503		53,449
Total assets	123,832		104,731
Short Term Debt	85,000		162,000
Short-term debt owed by PSE to Puget Energy	28,933		29,598
Total liabilities	$113,933		$191,598
[1]	Interest Rate Swap Contracts are only held at Puget Energy.
[2]	The valuation techniques, unobservable inputs and ranges are the same for asset and liability positions.

Fair_Value_Measurements_Debt_a

Fair Value Measurements - Debt at Carrying and Fair Value (Details) (Income Approach Valuation Technique, USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
PUGET SOUND ENERGY, INC. | Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Excluding Current Maturities, Fair Value Disclosure	$3,763,259	$3,763,258
PUGET SOUND ENERGY, INC. | Carrying Amount | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Junior subordinated notes	250,000	250,000
Long-term Debt, Fixed Rate, Net of Discount, Fair Value Disclosure	3,513,259	3,513,258
PUGET SOUND ENERGY, INC. | Total
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Excluding Current Maturities, Fair Value Disclosure	4,713,708	4,307,821
PUGET SOUND ENERGY, INC. | Total | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Junior subordinated notes	276,235	269,366
Long-term Debt, Fixed Rate, Net of Discount, Fair Value Disclosure	4,437,473	4,038,455
PUGET ENERGY | Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Excluding Current Maturities, Fair Value Disclosure	5,243,608	5,232,476
PUGET ENERGY | Carrying Amount | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Junior subordinated notes	250,000	250,000
Long-term Debt, Fixed Rate, Net of Discount, Fair Value Disclosure	4,694,608	4,683,476
Long-term Debt, Variable Rate, Net of Discount, Fair Value Disclosure	299,000	299,000
PUGET ENERGY | Total
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Excluding Current Maturities, Fair Value Disclosure	6,658,789	6,162,680
PUGET ENERGY | Total | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Junior subordinated notes	276,235	269,366
Long-term Debt, Fixed Rate, Net of Discount, Fair Value Disclosure	6,083,554	5,594,314
Long-term Debt, Variable Rate, Net of Discount, Fair Value Disclosure	$299,000	$299,000

Fair_Value_Measurements_Unobse

Fair Value Measurements - Unobservable Input Reconciliation (Details) (USD $)	12 Months Ended						6 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012		Jun. 30, 2013	Jul. 01, 2013	Mar. 31, 2012
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Finite-lived Intangible Assets, Fair Value Disclosure	$437,600,000							$484,100,000
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	-15,782,000		-35,526,000		-95,352,000		-35,526,000
Included in earnings	-5,537,000	[1]	-10,491,000	[1]	-21,362,000	[1]
Included in regulatory assets / liabilities	1,630,000		-945,000		-1,937,000
Settlements	-498,000	[2]	10,855,000	[2]	60,102,000	[2]
Transferred into Level 3	4,570,000		-7,799,000		-55,845,000
Transferred out of Level 3	1,515,000		28,124,000		78,868,000
Balance at end of period	-14,102,000		-15,782,000		-35,526,000
Electric Portfolio
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	-15,421,000		-33,924,000		-90,311,000		-33,924,000
Included in earnings	-5,537,000	[1]	-10,491,000	[1]	-21,362,000	[1]
Included in regulatory assets / liabilities	0		0		0
Settlements	1,036,000	[2]	11,609,000	[2]	59,133,000	[2]
Transferred into Level 3	5,155,000		-7,799,000		-55,548,000
Transferred out of Level 3	2,705,000		25,184,000		74,164,000
Balance at end of period	-12,062,000		-15,421,000		-33,924,000
Unrealized gain (loss) on derivative instruments, net	-9,600,000		-13,400,000		-15,200,000
Natural Gas Portfolio
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	-361,000		-1,602,000		-5,041,000		-1,602,000
Included in earnings	0	[1]	0	[1]	0	[1]
Included in regulatory assets / liabilities	1,630,000		-945,000		-1,937,000
Settlements	-1,534,000	[2]	-754,000	[2]	969,000	[2]
Transferred into Level 3	-585,000		0		-297,000
Transferred out of Level 3	-1,190,000		2,940,000		4,704,000
Balance at end of period	-2,040,000		-361,000		-1,602,000
Wells Project
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Finite-Lived Intangible Assets, Net	65,300,000
Reported Value Measurement [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Finite-lived Intangible Assets, Fair Value Disclosure	62,100,000							33,600,000
Portion at Fair Value Measurement [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Finite-lived Intangible Assets, Fair Value Disclosure								13,500,000	3,200,000
Income Approach Valuation Technique | Minimum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Price Per Megawatt-Hour	19.3						30.85
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Inputs, Power Contract Costs	3,015,000						389,000
Income Approach Valuation Technique | Maximum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Price Per Megawatt-Hour	37.06						65.35
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Inputs, Power Contract Costs	4,783,000						6,845,000
Income Approach Valuation Technique | Weighted Average
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Price Per Megawatt-Hour	29.53						48.47
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Inputs, Power Contract Costs	$4,469,000						$4,110,000
[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 $(9.6) million, $(13.4) million, and $(15.2) million for the years ended December 31, 2014, 2013 and 2012, respectively.
[2]	The Company had no purchases, sales or issuances during the reported periods.

Fair_Value_Measurements_Valuat

Fair Value Measurements - Valuation Techniques (Details) (USD $)	6 Months Ended	12 Months Ended
	Jun. 30, 2013	Dec. 31, 2014		Jul. 01, 2013	Dec. 31, 2013	Mar. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value measurement, sensitivity analysis, hypothetical increase or decrease of market prices, result on fair value, percent		10.00%
Fair Value Measurements, Sensitivity Analysis, Hypothetical Increase or Decrease of Market Prices, Result on Fair Value		($3,900,000)
Intangible asset fair value		437,600,000		484,100,000
Income Approach Valuation Technique | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Inputs, Price Per Megawatt-Hour	30.85	19.3
Fair Value Inputs, Power Contract Costs	389,000	3,015,000
Income Approach Valuation Technique | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Inputs, Price Per Megawatt-Hour	65.35	37.06
Fair Value Inputs, Power Contract Costs	6,845,000	4,783,000
Income Approach Valuation Technique | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Inputs, Price Per Megawatt-Hour	48.47	29.53
Fair Value Inputs, Power Contract Costs	4,110,000	4,469,000
PUGET ENERGY | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities		0			0
Commodity Contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		24,348,000			26,600,000
Derivative liabilities		196,035,000			72,988,000
Commodity Contract | Electric Portfolio | PUGET ENERGY | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		3,168,000	[1]
Derivative liabilities		15,230,000	[1]
Commodity Contract | Natural Gas Portfolio | PUGET ENERGY | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		1,462,000	[1]
Derivative liabilities		3,502,000	[1]
Electric Portfolio | Income Approach Valuation Technique | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Inputs, Price Per Megawatt-Hour		21.79
Electric Portfolio | Income Approach Valuation Technique | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Inputs, Price Per Megawatt-Hour		35.46
Electric Portfolio | Income Approach Valuation Technique | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Inputs, Price Per Megawatt-Hour		32.89
Natural Gas Portfolio | Income Approach Valuation Technique | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Inputs, Price Per Millions of BTU		3.11
Natural Gas Portfolio | Income Approach Valuation Technique | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Inputs, Price Per Millions of BTU		3.83
Natural Gas Portfolio | Income Approach Valuation Technique | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Inputs, Price Per Millions of BTU		3.28
Priest Rapids Development
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Intangible asset carrying value				47,100,000
Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Intangible asset fair value		62,100,000		33,600,000
Portion at Fair Value, Fair Value Disclosure
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Intangible asset fair value				$13,500,000		$3,200,000
[1]	The valuation techniques, unobservable inputs and ranges are the same for asset and liability positions.

Employee_Investment_Plans_Deta

Employee Investment Plans (Details) (PUGET SOUND ENERGY, INC., USD $)	3 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2012	Dec. 31, 2010
Defined Contribution Plan
Employer matching contribution, percent	1.00%	4.00%
Employer discretionary contribution amount		$14.90	$14.60	$14.50
6 percent
Defined Contribution Plan
Employer matching contribution, percent		4.50%
Maximum annual contribution per employee, percent		6.00%
Cash Balance Formula
Defined Contribution Plan
Employer matching contribution, percent		100.00%
Maximum annual contribution per employee, percent		6.00%
Employer additional contribution of base pay, percentage		1.00%
Cash Balance Formula | First 3 Percent
Defined Contribution Plan
Employer matching contribution, percent		100.00%
Maximum annual contribution per employee, percent		3.00%
Cash Balance Formula | Second 3 Percent
Defined Contribution Plan
Employer matching contribution, percent		50.00%
Maximum annual contribution per employee, percent		3.00%
Final Average Earnings Formula
Defined Contribution Plan
Employer matching contribution, percent		55.00%
Maximum annual contribution per employee, percent		6.00%

Retirement_Benefits_Change_in_

Retirement Benefits - Change in Net Benefit Obligation and Fair Value (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Qualified Pension Benefits
Change in benefit obligation:
Benefit obligation at beginning of period	$573,317	$616,290
Service cost	17,437	19,285	16,926
Interest cost	28,039	24,754	25,986
Amendment	0	0
Actuarial loss (gain)	104,618	-48,559
Benefits paid	-33,217	-38,453
Medicare part D subsidy received	0	0
Benefit obligation at end of period	690,194	573,317	616,290
Change in plan assets:
Fair value of plan assets at beginning of period	615,721	531,183
Actual return on plan assets	25,669	102,591
Employer contribution	18,000	20,400
Benefits paid	-33,217	-38,453
Fair value of plan assets at end of period	626,173	615,721	531,183
Funded status at end of period	-64,021	42,404
SERP Pension Benefits
Change in benefit obligation:
Benefit obligation at beginning of period	47,279	51,795
Service cost	1,042	1,498
Interest cost	2,310	2,045
Amendment	0	478
Actuarial loss (gain)	7,162	-1,687
Benefits paid	-1,938	-6,850
Medicare part D subsidy received	0	0
Benefit obligation at end of period	55,855	47,279
Change in plan assets:
Fair value of plan assets at beginning of period	0	0
Actual return on plan assets	0	0
Employer contribution	1,938	6,850
Benefits paid	-1,938	-6,850
Fair value of plan assets at end of period	0	0
Funded status at end of period	-55,855	-47,279
Other Benefits
Change in benefit obligation:
Benefit obligation at beginning of period	14,939	17,672
Service cost	112	134	139
Interest cost	684	664	751
Amendment	0	0
Actuarial loss (gain)	1,108	-2,240
Benefits paid	-1,424	-1,536
Medicare part D subsidy received	269	245
Benefit obligation at end of period	15,688	14,939	17,672
Change in plan assets:
Fair value of plan assets at beginning of period	8,774	7,541
Actual return on plan assets	522	1,861
Employer contribution	488	908
Benefits paid	-1,424	-1,536
Fair value of plan assets at end of period	8,360	8,774	7,541
Funded status at end of period	-7,328	-6,165
PUGET SOUND ENERGY, INC. | Qualified Pension Benefits
Change in benefit obligation:
Service cost	17,437	19,285	16,926
Interest cost	28,039	24,753	25,986
PUGET SOUND ENERGY, INC. | Other Benefits
Change in benefit obligation:
Service cost	112	134	139
Interest cost	$684	$664	$751

Retirement_Benefits_Amounts_Re

Retirement Benefits - Amounts Recognized (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan, Amounts Recognized in Accumulated Other Comprehensive Income Consist of: [Abstract]
Total	$36,710	($48,514)
Qualified Pension Benefits
Defined Benefit Plan, Amounts Recognized in Statement of Financial Position Consist of: [Abstract]
Noncurrent assets	0	42,404
Current liabilities	0	0
Noncurrent liabilities	-64,021	0
Net assets (liabilities)	-64,021	42,404
Other changes (pre-tax) in plan assets and benefit obligations recognized in other comprehensive income:
Net loss (gain)	121,413	-112,055
Amortization of net (loss) gain	0	-2,889
Prior service cost (credit)	0	0
Amortization of prior service cost (credit)	1,980	1,980
Total change in other comprehensive income for year	123,393	-112,964
Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan, Amounts Recognized in Statement of Financial Position Consist of: [Abstract]
Noncurrent assets	0	0
Current liabilities	-4,386	-3,981
Noncurrent liabilities	-51,469	-43,298
Net assets (liabilities)	-55,855	-47,279
Other changes (pre-tax) in plan assets and benefit obligations recognized in other comprehensive income:
Net loss (gain)	7,162	-1,687
Amortization of net (loss) gain	-913	-1,461
Prior service cost (credit)	0	478
Amortization of prior service cost (credit)	-42	17
Total change in other comprehensive income for year	6,207	-2,653
Other Benefits
Defined Benefit Plan, Amounts Recognized in Statement of Financial Position Consist of: [Abstract]
Noncurrent assets	0	0
Current liabilities	-355	-421
Noncurrent liabilities	-6,973	-5,744
Net assets (liabilities)	-7,328	-6,165
Other changes (pre-tax) in plan assets and benefit obligations recognized in other comprehensive income:
Net loss (gain)	1,121	-3,665
Amortization of net (loss) gain	394	-70
Prior service cost (credit)	0	0
Amortization of prior service cost (credit)	0	0
Total change in other comprehensive income for year	1,515	-3,735
PUGET ENERGY | Qualified Pension Benefits
Defined Benefit Plan, Amounts Recognized in Accumulated Other Comprehensive Income Consist of: [Abstract]
Net loss (gain)	55,471	-65,943
Prior service cost (credit)	-13,782	-15,762
Total	41,689	-81,705
PUGET ENERGY | Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan, Amounts Recognized in Accumulated Other Comprehensive Income Consist of: [Abstract]
Net loss (gain)	15,918	9,670
Prior service cost (credit)	331	373
Total	16,249	10,043
PUGET ENERGY | Other Benefits
Defined Benefit Plan, Amounts Recognized in Accumulated Other Comprehensive Income Consist of: [Abstract]
Net loss (gain)	-1,457	-2,972
Prior service cost (credit)	0	0
Total	-1,457	-2,972
PUGET SOUND ENERGY, INC.
Defined Benefit Plan, Amounts Recognized in Accumulated Other Comprehensive Income Consist of: [Abstract]
Total	164,281	87,405
PUGET SOUND ENERGY, INC. | Qualified Pension Benefits
Defined Benefit Plan, Amounts Recognized in Accumulated Other Comprehensive Income Consist of: [Abstract]
Net loss (gain)	247,331	138,324
Prior service cost (credit)	-10,952	-12,525
Total	236,379	125,799
Other changes (pre-tax) in plan assets and benefit obligations recognized in other comprehensive income:
Net loss (gain)	122,202	-110,465
Amortization of net (loss) gain	-13,195	-20,612
Prior service cost (credit)	0	0
Amortization of prior service cost (credit)	1,573	1,573
Amortization of transition obligation	0	0
Total change in other comprehensive income for year	110,580	-129,504
PUGET SOUND ENERGY, INC. | Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan, Amounts Recognized in Accumulated Other Comprehensive Income Consist of: [Abstract]
Net loss (gain)	19,751	14,050
Prior service cost (credit)	339	383
Total	20,090	14,433
Other changes (pre-tax) in plan assets and benefit obligations recognized in other comprehensive income:
Net loss (gain)	7,162	-1,687
Amortization of net (loss) gain	-1,461	-2,191
Prior service cost (credit)	0	477
Amortization of prior service cost (credit)	-44	16
Amortization of transition obligation	0	0
Total change in other comprehensive income for year	5,657	-3,385
PUGET SOUND ENERGY, INC. | Other Benefits
Defined Benefit Plan, Amounts Recognized in Accumulated Other Comprehensive Income Consist of: [Abstract]
Net loss (gain)	-3,733	-5,556
Prior service cost (credit)	3	6
Total	-3,730	-5,550
Other changes (pre-tax) in plan assets and benefit obligations recognized in other comprehensive income:
Net loss (gain)	1,121	-3,665
Amortization of net (loss) gain	702	284
Prior service cost (credit)	0	0
Amortization of prior service cost (credit)	-3	-30
Amortization of transition obligation	0	0
Total change in other comprehensive income for year	$1,820	($3,411)

Retirement_Benefits_Net_Period

Retirement Benefits - Net Periodic Benefit Cost (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Qualified Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Noncurrent assets	$0	$42,404
Components of net periodic benefit cost:
Service cost	17,437	19,285	16,926
Interest cost	28,039	24,754	25,986
Expected return on plan assets	-42,464	-39,095	-36,203
Amortization of prior service cost (credit)	-1,980	-1,980	-1,980
Amortization of net loss	0	2,889	768
Net periodic benefit cost	1,032	5,853	5,497
Pension and Other Postretirement Defined Benefit Plans, Current Liabilities	0	0
Pension and Other Postretirement Defined Benefit Plans, Liabilities, Noncurrent	64,021	0
Defined Benefit Plan, Amounts Recognized in Balance Sheet	-64,021	42,404
Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Noncurrent assets	0	0
Components of net periodic benefit cost:
Service cost	1,042	1,498	1,073
Interest cost	2,310	2,045	2,152
Expected return on plan assets	0	0	0
Amortization of prior service cost (credit)	42	-17	0
Amortization of net loss	913	1,461	702
Net periodic benefit cost	4,307	4,987	3,927
Pension and Other Postretirement Defined Benefit Plans, Current Liabilities	4,386	3,981
Pension and Other Postretirement Defined Benefit Plans, Liabilities, Noncurrent	51,469	43,298
Defined Benefit Plan, Amounts Recognized in Balance Sheet	-55,855	-47,279
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Noncurrent assets	0	0
Components of net periodic benefit cost:
Service cost	112	134	139
Interest cost	684	664	751
Expected return on plan assets	-535	-436	-435
Amortization of prior service cost (credit)	0	0	0
Amortization of net loss	-393	69	53
Net periodic benefit cost	-132	431	508
Pension and Other Postretirement Defined Benefit Plans, Current Liabilities	355	421
Pension and Other Postretirement Defined Benefit Plans, Liabilities, Noncurrent	6,973	5,744
Defined Benefit Plan, Amounts Recognized in Balance Sheet	-7,328	-6,165
PUGET SOUND ENERGY, INC. | Qualified Pension Benefits
Components of net periodic benefit cost:
Service cost	17,437	19,285	16,926
Interest cost	28,039	24,753	25,986
Expected return on plan assets	-43,252	-40,685	-41,533
Amortization of prior service cost (credit)	-1,573	-1,573	-1,573
Amortization of net loss	13,195	20,612	15,015
Amortization of transition obligation	0	0	0
Net periodic benefit cost	13,846	22,392	14,821
PUGET SOUND ENERGY, INC. | Supplemental Employee Retirement Plan [Member]
Components of net periodic benefit cost:
Service cost	1,042	1,498	1,073
Interest cost	2,310	2,045	2,152
Expected return on plan assets	0	0	0
Amortization of prior service cost (credit)	44	-16	293
Amortization of net loss	1,461	2,191	1,432
Amortization of transition obligation	0	0	0
Net periodic benefit cost	4,857	5,718	4,950
PUGET SOUND ENERGY, INC. | Other Benefits
Components of net periodic benefit cost:
Service cost	112	134	139
Interest cost	684	664	751
Expected return on plan assets	-535	-436	-435
Amortization of prior service cost (credit)	3	30	35
Amortization of net loss	-702	-284	-245
Amortization of transition obligation	0	0	50
Net periodic benefit cost	($438)	$108	$295

Retirement_Benefits_Assumption

Retirement Benefits - Assumptions (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Benefit Obligation Assumptions
Discount rate	4.25%
Assumed Health Care Cost Trend Rates
Medical inflation rate assumed for next fiscal year	6.70%
Ultimate health care cost trend rate	4.30%
Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rates
1% Increase, Effect on post-retirement benefit obligation	47		66
1% Decrease, Effect on post-retirement benefit obligation	-47		-66
1% Increase, Effect on service and interest cost components	2		3
1% Decrease, Effect on service and interest cost components	-2		-3
Qualified Pension Benefits
Benefit Obligation Assumptions
Discount rate	4.25%	[1]	5.10%	[1]	4.15%	[1]
Rate of compensation increase	4.50%		4.50%		4.50%
Medical trend rate	0.00%		0.00%		0.00%
Benefit Cost Assumptions
Discount rate	5.10%		4.15%		4.75%
Rate of plan assets	7.75%		7.75%		7.75%
Rate of compensation increase	4.50%		4.50%		4.50%
Medical trend rate	0.00%		0.00%		0.00%
SERP Pension Benefits
Benefit Obligation Assumptions
Discount rate	4.25%	[1]	5.10%	[1]	4.15%	[1]
Rate of compensation increase	4.50%		4.50%		4.50%
Medical trend rate	0.00%		0.00%		0.00%
Benefit Cost Assumptions
Discount rate	5.10%		4.15%		4.75%
Rate of plan assets	0.00%		0.00%		0.00%
Rate of compensation increase	4.50%		4.50%		4.50%
Medical trend rate	0.00%		0.00%		0.00%
Other Benefits
Benefit Obligation Assumptions
Discount rate	4.25%	[1]	5.10%	[1]	4.15%	[1]
Rate of compensation increase	4.50%		4.50%		4.50%
Medical trend rate	5.70%		6.80%		7.50%
Benefit Cost Assumptions
Discount rate	5.10%		4.15%		4.75%
Rate of plan assets	7.00%		6.90%		7.50%
Rate of compensation increase	4.50%		4.50%		4.50%
Medical trend rate	6.70%		8.20%		7.50%
[1]	The Company calculates the present value of the pension liability using a discount rate of 4.25% which represents the single-rate equivalent of the AA rated corporate bond yield curve.

Retirement_Benefits_Future_Ben

Retirement Benefits - Future Benefit Payments (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Qualified Pension Benefits
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Expected Return on Plan Assets	$42,464	$39,095	$36,203
2015	41,100
2015	41,400
2016	42,100
2017	43,300
2018	43,900
2019-2023	237,300
Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Expected Return on Plan Assets	0	0	0
SERP Pension Benefits
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
2015	4,386
2015	2,595
2016	1,940
2017	5,346
2018	5,811
2019-2023	18,759
Other Benefits
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Expected Return on Plan Assets	535	436	435
2015	1,080
2015	1,136
2016	1,113
2017	1,085
2018	1,062
2019-2023	5,935
2014, without Medicare Part D subsidy	1,429
2015, without Medicare Part D subsidy	1,414
2016, without Medicare Part D subsidy	1,398
2017, without Medicare Part D subsidy	1,380
2018, without Medicare Part D subsidy	1,362
2019-2023, without Medicare Part D subsidy	$6,340

Retirement_Benefits_Plan_Asset

Retirement Benefits - Plan Asset Allocation (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Qualified Pension Benefits
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	626,173		$615,721		$531,183
Other Benefits
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	8,360		8,774		7,541
SERP Pension Benefits
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0		0		0
Domestic large cap equity
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target Allocation, Minimum	25.00%
Target Allocation	31.00%
Target Allocation, Maximum	40.00%
Domestic small cap equity
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target Allocation, Minimum	0.00%
Target Allocation	9.00%
Target Allocation, Maximum	15.00%
Non-U.S. equity
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target Allocation, Minimum	10.00%
Target Allocation	25.00%
Target Allocation, Maximum	30.00%
Fixed income
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target Allocation, Minimum	15.00%
Target Allocation	25.00%
Target Allocation, Maximum	30.00%
Real estate
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target Allocation, Minimum	0.00%
Target Allocation	0.00%
Target Allocation, Maximum	10.00%
Absolute return
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target Allocation, Minimum	5.00%
Target Allocation	10.00%
Target Allocation, Maximum	15.00%
Cash and cash equivalents
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target Allocation, Minimum	0.00%
Target Allocation	0.00%
Target Allocation, Maximum	5.00%
Fair Value, Measurements, Recurring | Qualified Pension Benefits | Level 3
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	65,251		62,278		55,614
Fair Value, Measurements, Recurring | Qualified Pension Benefits | Total
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	626,173		615,721
Fair Value, Measurements, Recurring | Other Benefits | Level 1
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	8,360		8,703
Fair Value, Measurements, Recurring | Other Benefits | Level 2
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0		71
Fair Value, Measurements, Recurring | Other Benefits | Total
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	8,360		8,774
Fair Value, Measurements, Recurring | Subtotal | Qualified Pension Benefits | Level 1
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	350,429		431,936
Fair Value, Measurements, Recurring | Subtotal | Qualified Pension Benefits | Level 2
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	209,649		121,721
Fair Value, Measurements, Recurring | Subtotal | Qualified Pension Benefits | Level 3
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	65,251		62,278
Fair Value, Measurements, Recurring | Subtotal | Qualified Pension Benefits | Total
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	625,329		615,935
Fair Value, Measurements, Recurring | Equities: | Qualified Pension Benefits | Level 1
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	265,448		296,929
Fair Value, Measurements, Recurring | Equities: | Qualified Pension Benefits | Level 2
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	142,467		114,667
Fair Value, Measurements, Recurring | Equities: | Qualified Pension Benefits | Level 3
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0		0
Fair Value, Measurements, Recurring | Equities: | Qualified Pension Benefits | Total
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	407,915		411,596
Fair Value, Measurements, Recurring | Domestic large cap equity | Qualified Pension Benefits | Level 1
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	134,765	[1]	157,874	[1]
Fair Value, Measurements, Recurring | Domestic large cap equity | Qualified Pension Benefits | Level 2
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	68,336	[1]	35,851	[1]
Fair Value, Measurements, Recurring | Domestic large cap equity | Qualified Pension Benefits | Level 3
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Fair Value, Measurements, Recurring | Domestic large cap equity | Qualified Pension Benefits | Total
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	203,101	[1]	193,725	[1]
Fair Value, Measurements, Recurring | Domestic small cap equity | Qualified Pension Benefits | Level 1
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	59,657	[2]	62,867	[2]
Fair Value, Measurements, Recurring | Domestic small cap equity | Qualified Pension Benefits | Level 2
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[2]	0	[2]
Fair Value, Measurements, Recurring | Domestic small cap equity | Qualified Pension Benefits | Level 3
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[2]	0	[2]
Fair Value, Measurements, Recurring | Domestic small cap equity | Qualified Pension Benefits | Total
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	59,657	[2]	62,867	[2]
Fair Value, Measurements, Recurring | Non-U.S. equity | Qualified Pension Benefits | Level 1
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	71,026	[3]	76,188	[3]
Fair Value, Measurements, Recurring | Non-U.S. equity | Qualified Pension Benefits | Level 2
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	74,131	[3]	78,816	[3]
Fair Value, Measurements, Recurring | Non-U.S. equity | Qualified Pension Benefits | Level 3
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[3]	0	[3]
Fair Value, Measurements, Recurring | Non-U.S. equity | Qualified Pension Benefits | Total
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	145,157	[3]	155,004	[3]
Fair Value, Measurements, Recurring | Tactical asset allocation | Qualified Pension Benefits | Level 1
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[4]	0	[4]
Fair Value, Measurements, Recurring | Tactical asset allocation | Qualified Pension Benefits | Level 2
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[4]	0	[4]
Fair Value, Measurements, Recurring | Tactical asset allocation | Qualified Pension Benefits | Level 3
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[4]	0	[4]
Fair Value, Measurements, Recurring | Tactical asset allocation | Qualified Pension Benefits | Total
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[4]	0	[4]
Fair Value, Measurements, Recurring | Fixed income | Qualified Pension Benefits | Level 1
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	72,331	[5]	135,007	[5]
Fair Value, Measurements, Recurring | Fixed income | Qualified Pension Benefits | Level 2
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	67,182	[5]	0	[5]
Fair Value, Measurements, Recurring | Fixed income | Qualified Pension Benefits | Level 3
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[5]	0	[5]
Fair Value, Measurements, Recurring | Fixed income | Qualified Pension Benefits | Total
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	139,513	[5]	135,007	[5]
Fair Value, Measurements, Recurring | Absolute return | Qualified Pension Benefits | Level 1
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[6]	0	[6]
Fair Value, Measurements, Recurring | Absolute return | Qualified Pension Benefits | Level 2
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[6]	0	[6]
Fair Value, Measurements, Recurring | Absolute return | Qualified Pension Benefits | Level 3
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	65,251	[6]	62,278	[6]
Fair Value, Measurements, Recurring | Absolute return | Qualified Pension Benefits | Total
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	65,251	[6]	62,278	[6]
Fair Value, Measurements, Recurring | Mutual Funds | Qualified Pension Benefits | Level 3
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0		0		0
Fair Value, Measurements, Recurring | Mutual Funds | Other Benefits | Level 1
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	8,301	[7]	8,703	[7]
Fair Value, Measurements, Recurring | Mutual Funds | Other Benefits | Level 2
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[7]	0	[7]
Fair Value, Measurements, Recurring | Mutual Funds | Other Benefits | Total
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	8,301	[7]	8,703	[7]
Fair Value, Measurements, Recurring | Cash and cash equivalents | Qualified Pension Benefits | Level 1
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	12,650	[8]	0	[8]
Fair Value, Measurements, Recurring | Cash and cash equivalents | Qualified Pension Benefits | Level 2
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[8]	7,054	[8]
Fair Value, Measurements, Recurring | Cash and cash equivalents | Qualified Pension Benefits | Level 3
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[8]	0	[8]
Fair Value, Measurements, Recurring | Cash and cash equivalents | Qualified Pension Benefits | Total
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	12,650	[8]	7,054	[8]
Fair Value, Measurements, Recurring | Cash and cash equivalents | Other Benefits | Level 1
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	59	[9]	0	[9]
Fair Value, Measurements, Recurring | Cash and cash equivalents | Other Benefits | Level 2
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[9]	71	[9]
Fair Value, Measurements, Recurring | Cash and cash equivalents | Other Benefits | Total
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	59	[9]	71	[9]
Fair Value, Measurements, Recurring | Net (payable) receivable | Qualified Pension Benefits | Total
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	844		-417
Fair Value, Measurements, Recurring | Accrued income | Qualified Pension Benefits | Total
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0		$203
[1]	Domestic large cap equity investments are comprised of (1) common stock, and a (2) commingled fund. Investments in common stock are valued using quoted market prices multiplied by the number of shares owned as of December 31, 2014. The investment in the commingled fund is valued at the net asset value per share multiplied by the number of shares held as of December 31, 2014.
[2]	Domestic small cap equity investments are comprised of (1) common stock and a (2) mutual fund. The investments in common stock are valued using quoted market prices multiplied by the number of shares owned as of December 31, 2014. The investment in the mutual fund is valued using quoted market prices multiplied by the number of shares owned as of December 31, 2014.
[3]	Non – US Equity investments are comprised of a (1) mutual fund; and a (2) commingled fund. The investment in the mutual fund is valued using quoted market prices multiplied by the number of shares owned as of December 31, 2014. The investment in the commingled fund is valued at the net asset value per share multiplied by the number of shares held as of December 31, 2014.
[4]	The tactical asset allocation investment is comprised of a commingled fund, which is valued at the net asset value per share multiplied by the number of shares held as of the measurement date.
[5]	Fixed income securities consist of a mutual fund. The investment in the mutual fund is valued using quoted market prices multiplied by the number of shares owned as of December 31, 2014.
[6]	As of December 31, 2014 absolute return investments consist of two partnerships. The partnerships are valued using the financial reports as of December 31, 2014. These investments are a Level 3 under ASC 820 because the significant valuation inputs are primarily internal to the partnerships with little third party involvement.
[7]	This is a publicly traded balanced mutual fund. The fund seeks regular income, conservation of principal, and an opportunity for long-term growth of principal and income. The fair value is determined by taking the number of shares owned by the plan, and multiplying by the market price as of December 31, 2014.
[8]	The investment consists of a money market fund, which is valued at the net asset value per share of $1.00 per unit as of December 31, 2014. The money market fund invests primarily in commercial paper, notes, repurchase agreements, and other evidences of indebtedness which are payable on demand or short-term in nature.
[9]	This is a money market fund. The money market fund investments are valued at the net asset value per share of $1.00 per unit as of December 31, 2014. The money market fund invests primarily in commercial paper, notes, repurchase agreements, and other evidences of indebtedness which are payable on demand or short-term in nature.

Retirement_Benefits_Fair_Value

Retirement Benefits - Fair Value Level 3 Rollforward (Details) (Qualified Pension Benefits, USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Change in plan assets:
Fair value of plan assets at beginning of period					$531,183
Fair value of plan assets at end of period	626,173		615,721		531,183
Fair Value, Measurements, Recurring | Level 3
Change in plan assets:
Fair value of plan assets at beginning of period	62,278		55,614
Additional investments	0		0
Distributions	0		0
Realized losses on distributions	0		0
Unrealized gains relating to instruments still held at the reporting date	2,973		6,664
Transferred out of level 3	0	[1]	0	[1]
Fair value of plan assets at end of period	65,251		62,278
Fair Value, Measurements, Recurring | Partnership | Level 3
Change in plan assets:
Fair value of plan assets at beginning of period	62,278		55,614
Additional investments	0		0
Distributions	0		0
Realized losses on distributions	0		0
Unrealized gains relating to instruments still held at the reporting date	2,973		6,664
Transferred out of level 3	0	[1]	0	[1]
Fair value of plan assets at end of period	65,251		62,278
Fair Value, Measurements, Recurring | Mutual Funds | Level 3
Change in plan assets:
Fair value of plan assets at beginning of period	0		0
Additional investments	0		0
Distributions	0		0
Realized losses on distributions	0		0
Unrealized gains relating to instruments still held at the reporting date	0		0
Transferred out of level 3	0	[1]	0	[1]
Fair value of plan assets at end of period	$0		$0
[1]	The plan had no transfers between level 2 and level 1 during the years ended December 31, 2014 or 2013.

Retirement_Benefits_Textuals_D

Retirement Benefits - Textuals (Details) (USD $)	12 Months Ended	3 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2015
Qualified Pension Benefits
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension and Other Postretirement Benefit Plans, Net Prior Service Cost or Credit, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year	$3.90
SERP Pension Benefits
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year, Net Gain (Loss)	1.6
PUGET SOUND ENERGY, INC.
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Contribution Plan, Employer Matching Contribution, Percent	4.00%	1.00%
PUGET SOUND ENERGY, INC. | Qualified Pension Benefits
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year, Net Gain (Loss)	20.5
Pension and Other Postretirement Benefit Plans, Net Prior Service Cost or Credit, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year	1.6
PUGET SOUND ENERGY, INC. | SERP Pension Benefits
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year, Net Gain (Loss)	2.1
PUGET SOUND ENERGY, INC. | Other Benefits
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year, Net Gain (Loss)	0.3
Cash Balance Formula | PUGET SOUND ENERGY, INC.
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Contribution Plan, Employer Matching Contribution, Percent	100.00%
Final Average Earnings Formula | PUGET SOUND ENERGY, INC.
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Contribution Plan, Employer Matching Contribution, Percent	55.00%
PUGET SOUND ENERGY, INC. | Qualified Pension Benefits
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Estimated Future Employer Contributions in Current Fiscal Year			18
PUGET SOUND ENERGY, INC. | SERP Pension Benefits
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Estimated Future Employer Contributions in Current Fiscal Year			4.4
PUGET SOUND ENERGY, INC. | Other Benefits
Defined Benefit Plan and Other Postretirement Benefit Plans Table Text Block [Line Items]
Estimated Future Employer Contributions in Current Fiscal Year			$0.50

Retirement_Benefits_Accumulate

Retirement Benefits Accumulated Benefit Obligation (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
SERP Pension Benefits
Defined Contribution Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation	$55,855	$47,279	$51,795
Defined Benefit Plan, Accumulated Benefit Obligation	50,137	40,892
Defined Benefit Plan, Fair Value of Plan Assets	0	0	0
Other Pension Plan [Member]
Defined Contribution Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation	15,688	14,939	17,672
Defined Benefit Plan, Accumulated Benefit Obligation	15,553	14,794
Defined Benefit Plan, Fair Value of Plan Assets	8,360	8,774	7,541
Qualified Pension Benefits
Defined Contribution Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation	690,194	573,317	616,290
Defined Benefit Plan, Accumulated Benefit Obligation	681,745	566,689
Defined Benefit Plan, Fair Value of Plan Assets	$626,173	$615,721	$531,183

Income_Taxes_Components_of_Inc

Income Taxes - Components of Income Tax Expense (Benefit) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosures [Line Items]
Federal	$0	$0	$4,268
State	0	0	0
Federal	57,152	122,559	100,701
State	-167	-151	-244
Total income tax expense	56,985	122,408	104,725
PUGET SOUND ENERGY, INC.
Income Tax Disclosures [Line Items]
Federal	0	0	4,268
State	0	0	0
Federal	89,342	160,886	145,040
State	0	0	0
Total income tax expense	$89,342	$160,886	$149,308

Income_Taxes_Income_Tax_Reconc

Income Taxes - Income Tax Reconciliation (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosures [Line Items]
Federal statutory rate	35.00%
Income Tax Reconciliation [Abstract]
Income taxes at the statutory rate	$80,087	$142,847	$132,491
Production tax credit	-23,073	-22,414	-22,188
AFUDC excluded from taxable income	-3,790	-9,406	-16,543
Capitalized interest	2,947	7,294	9,757
Utility plant differences	7,090	9,527	8,674
Income Tax Reconciliation, Treasury Grant	-8,808	-7,651	-1,007
Tenaska gas contract	0	1	-4,687
Other - net	2,532	2,210	-1,772
Total income tax expense	56,985	122,408	104,725
Effective tax rate	24.90%	30.00%	27.70%
PUGET SOUND ENERGY, INC.
Income Tax Reconciliation [Abstract]
Income taxes at the statutory rate	114,084	180,955	176,917
Production tax credit	-23,073	-22,414	-22,188
AFUDC excluded from taxable income	-3,790	-9,406	-16,543
Capitalized interest	2,947	7,294	9,757
Utility plant differences	7,090	9,527	8,674
Income Tax Reconciliation, Treasury Grant	-8,808	-7,651	-1,007
Tenaska gas contract	0	1	-4,687
Other - net	892	2,580	-1,615
Total income tax expense	$89,342	$160,886	$149,308
Effective tax rate	27.40%	31.10%	29.50%

Income_Taxes_Deferred_Income_T

Income Taxes - Deferred Income Taxes (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Deferred Tax Liabilities, Gross
Utility plant and equipment	$1,720,730	$1,625,107
Regulatory asset for income taxes	95,432	146,867
Fair value of debt instruments	73,606	76,991
Other deferred tax liabilities	200,124	202,189
Subtotal deferred tax liabilities	2,089,892	2,051,154
Deferred Tax Assets, Gross
Net operating loss carryforward	-417,684	-374,606
Production tax credit carryforward	-158,604	-135,531
Regulatory liability on production tax credit	-84,344	-71,880
Fair value of derivative instruments	-36,227	-7,166
Other deferred tax assets	-32,121	-60,970
Subtotal deferred tax assets	-728,980	-650,153
Total	1,360,912	1,401,001
PUGET SOUND ENERGY, INC.
Deferred Tax Liabilities, Gross
Utility plant and equipment	1,720,730	1,625,107
Regulatory asset for income taxes	94,913	146,350
Other deferred tax liabilities	171,380	131,977
Subtotal deferred tax liabilities	1,987,023	1,903,434
Deferred Tax Assets, Gross
Net operating loss carryforward	-181,514	-173,068
Production tax credit carryforward	-158,604	-135,531
Regulatory liability on production tax credit	-84,344	-71,880
Fair value of derivative instruments	-39,067	-9,988
Other deferred tax assets	-82,084	-69,175
Subtotal deferred tax assets	-545,613	-459,642
Total	$1,441,410	$1,443,792

Income_Taxes_Balance_Sheet_Loc

Income Taxes - Balance Sheet Location (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Income Tax Disclosures [Line Items]
Current deferred taxes	($161,445)	($86,004)
Non-current deferred taxes	1,522,357	1,487,005
Total	1,360,912	1,401,001
PUGET SOUND ENERGY, INC.
Income Tax Disclosures [Line Items]
Current deferred taxes	-208,447	-141,058
Non-current deferred taxes	1,649,857	1,584,850
Total	$1,441,410	$1,443,792

Litigation_Details

Litigation (Details) (USD $)	0 Months Ended
	Mar. 06, 2013	Dec. 31, 2014	Dec. 31, 2013
Pending Litigation
Loss Contingencies [Line Items]
Litigation claims accrual		$1,700,000	$1,400,000
Colstrip Unit One and Two
Loss Contingencies [Line Items]
Equity Method Investment, Ownership Percentage		50.00%
Colstrip Unit Three and Four
Loss Contingencies [Line Items]
Equity Method Investment, Ownership Percentage		25.00%
Sierra Club and Montana Environmental Information Center [Member] | Pending Litigation
Loss Contingencies [Line Items]
Loss Contingency, Damages Sought, Value	$100,000
Sierra Club and Montana Environmental Information Center [Member] | Failure to Update Title V Permit | Pending Litigation
Loss Contingencies [Line Items]
Loss Contingency, Pending Claims, Number	1
Sierra Club and Montana Environmental Information Center [Member] | Title V compliance certifications incomplete | Pending Litigation
Loss Contingencies [Line Items]
Loss Contingency, Pending Claims, Number	1
Sierra Club and Montana Environmental Information Center [Member] | Opacity | Pending Litigation
Loss Contingencies [Line Items]
Loss Contingency, Pending Claims, Number	1

Commitments_and_Contingencies_1

Commitments and Contingencies (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2010
	MW			MWh	MWh
	MWh
	Contracts
Long-term Purchase Commitment [Line Items]
Percentage of Company's energy output (percent)	14.90%
Average cost of Company's energy output (US$ per kWh)	0
Number of Public Utility Districts with long term purchase agreements	3
Contract expenses	$69,661,000		$63,365,000	$70,188,000
Megawatt Capacity	749
Estimated 2015 Costs	82,092,000
2015 Debt Service Costs	32,811,000
Interest included in 2015 Debt Service Costs	14,604,000
Debt Outstanding	256,077,000
Payment Obligations for Power Purchases
2014	206,531,000
2015	248,107,000
2016	285,730,000
2017	271,530,000
2018	264,426,000
Thereafter	1,998,857,000
Total	3,275,181,000
Total energy obtained during period under purchased power contracts (MWh)	12,100,000			10,700,000	6,100,000
Cost incurred during period to provide energy under purchased power contracts	401,400,000			348,700,000	203,100,000
Daily take obligation under long-term service contract (percent)	100.00%
Daily delivery obligation under long-term service contract (percent)	100.00%
Columbia River projects
Payment Obligations for Power Purchases
2014	73,023,000
2015	75,360,000
2016	74,851,000
2017	65,981,000
2018	53,837,000
Thereafter	644,666,000
Total	987,718,000
Other utilities
Payment Obligations for Power Purchases
2014	16,136,000
2015	18,884,000
2016	11,823,000
2017	1,257,000
2018	890,000
Thereafter	0
Total	48,990,000
Non-utility contracts
Payment Obligations for Power Purchases
2014	117,372,000
2015	153,863,000
2016	199,056,000
2017	204,292,000
2018	209,699,000
Thereafter	1,354,191,000
Total	2,238,473,000
Gas-fired generation facility
Payment Obligations for Power Purchases
2014	63,600,000
Purchase obligation under longer term (2013 through 2029) agreements	286,700,000
Short-term energy supply contracts
Payment Obligations for Power Purchases
2014	105,800,000
2015	32,400,000
2016	6,500,000
Firm transportation service
Payment Obligations for Power Purchases
2014	154,121,000
2015	147,424,000
2016	144,751,000
2017	131,484,000
2018	112,249,000
Thereafter	373,958,000
Total	1,063,987,000
Deman charges incurred under firm supply and service contracts	155,000,000
Firm storage service
Payment Obligations for Power Purchases
2014	6,528,000
2015	5,337,000
2016	5,209,000
2017	1,407,000
2018	1,535,000
Thereafter	1,258,000
Total	21,274,000
Deman charges incurred under firm supply and service contracts	6,600,000
Firm natural gas supply
Payment Obligations for Power Purchases
2014	160,649,000
2015	152,761,000
2016	149,960,000
2017	132,891,000
2018	113,784,000
Thereafter	375,216,000
Total	1,085,261,000
Combustion turbines
Payment Obligations for Power Purchases
Deman charges incurred under firm supply and service contracts	35,700,000
Energy production service contracts
Payment Obligations for Power Purchases
2014	32,979,000	[1]
2015	15,650,000	[1]
2016	5,558,000	[1]
2017	4,064,000	[1]
2018	2,372,000	[1]
Thereafter	23,443,000	[1]
Total	84,066,000	[1]
Automated meter reading system
Payment Obligations for Power Purchases
2014	25,402,000	[2]
2015	16,081,000	[2]
2016	13,362,000	[2]
2017	13,996,000	[2]
2018	14,602,000	[2]
Thereafter	51,986,000	[2]
Total	135,429,000	[2]
Service contract obligations
Payment Obligations for Power Purchases
2014	58,381,000
2015	31,731,000
2016	18,920,000
2017	18,060,000
2018	16,974,000
Thereafter	75,429,000
Total	219,495,000
Minimum | Combustion turbines
Payment Obligations for Power Purchases
Remaining terms under contract	less than one year
Maximum | Combustion turbines
Payment Obligations for Power Purchases
Remaining terms under contract	30
Rock Island Project
Long-term Purchase Commitment [Line Items]
Percent of Output	25.00%
Megawatt Capacity	156
Estimated 2015 Costs	29,854,000
2015 Debt Service Costs	11,009,000
Interest included in 2015 Debt Service Costs	6,174,000
Debt Outstanding	98,191,000
Rocky Reach Project
Long-term Purchase Commitment [Line Items]
Percent of Output	25.00%
Megawatt Capacity	325
Estimated 2015 Costs	27,583,000
2015 Debt Service Costs	8,245,000
Interest included in 2015 Debt Service Costs	3,343,000
Debt Outstanding	53,299,000
Wells Project
Long-term Purchase Commitment [Line Items]
Percent of Output	29.90%
Megawatt Capacity	251
Estimated 2015 Costs	17,277,000
2015 Debt Service Costs	9,383,000
Interest included in 2015 Debt Service Costs	2,597,000
Debt Outstanding	64,931,000
Priest Rapids Development
Long-term Purchase Commitment [Line Items]
Percent of Output	0.60%
Megawatt Capacity	8
Estimated 2015 Costs	3,689,000
2015 Debt Service Costs	2,087,000
Interest included in 2015 Debt Service Costs	1,245,000
Debt Outstanding	19,828,000
Wanapum Development
Long-term Purchase Commitment [Line Items]
Percent of Output	0.60%
Megawatt Capacity	9
Estimated 2015 Costs	3,689,000
2015 Debt Service Costs	2,087,000
Interest included in 2015 Debt Service Costs	1,245,000
Debt Outstanding	$19,828,000
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Related_Party_Transactions_Det

Related Party Transactions (Details) (PUGET SOUND ENERGY, INC., USD $)	Dec. 31, 2014	Dec. 31, 2013
Related Party Transaction [Line Items]
Debt Instrument, Fee Amount	$1,000,000
Short-term note owed to parent	$28,933,000	$29,598,000
Affiliated Entity [Member]
Related Party Transaction [Line Items]
Applicable interest rate on credit facility at period end	0.39%	0.33%

Segment_Information_Details

Segment Information (Details)	12 Months Ended
	Dec. 31, 2014
	segment
Segment Reporting Information [Line Items]
Number of operating segments	1
PUGET SOUND ENERGY, INC.
Segment Reporting Information [Line Items]
Area of service territory (sqmi)	6,000

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income (Loss) Changes in AOCI, net of tax (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss), net of tax	($37,043)	$47,715
Interest Rate Swap
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss), net of tax	-94	-3,022	-14,599
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0	0	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	94	2,928	11,577
Other Comprehensive Income (Loss), Net of Tax	94	2,928	11,577
Accumulated other comprehensive income (loss), net of tax	0	-94	-3,022
Accumulated Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss), net of tax	48,514	-29,065	-15,195
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	-84,301	76,004	-13,574
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	-923	1,575	-296
Other Comprehensive Income (Loss), Net of Tax	-85,224	77,579	-13,870
Accumulated other comprehensive income (loss), net of tax	-36,710	48,514	-29,065
Derivative
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss), net of tax	-705	-742	-1,113
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0	0	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	372	37	371
Other Comprehensive Income (Loss), Net of Tax	372	37	371
Accumulated other comprehensive income (loss), net of tax	-333	-705	-742
Comprehensive Income
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss), net of tax	47,715	-32,829	-30,907
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	-84,301	76,004	-13,574
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	-457	4,540	11,652
Other Comprehensive Income (Loss), Net of Tax	-84,758	80,544	-1,922
Accumulated other comprehensive income (loss), net of tax	-37,043	47,715	-32,829
PUGET SOUND ENERGY, INC.
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss), net of tax	-170,957	-95,739
PUGET SOUND ENERGY, INC. | Interest Rate Swap
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss), net of tax	-6,307	-6,624	-6,941
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0	0	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	317	317	317
Other Comprehensive Income (Loss), Net of Tax	317	317	317
Accumulated other comprehensive income (loss), net of tax	-5,990	-6,307	-6,624
PUGET SOUND ENERGY, INC. | Accumulated Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss), net of tax	-87,405	-175,998	-168,704
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	-84,955	74,969	-17,049
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	8,079	13,624	9,755
Other Comprehensive Income (Loss), Net of Tax	-76,876	88,593	-7,294
Accumulated other comprehensive income (loss), net of tax	-164,281	-87,405	-175,998
PUGET SOUND ENERGY, INC. | Derivative
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss), net of tax	-2,027	-4,576	-12,934
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0	0	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	1,341	2,549	8,358
Other Comprehensive Income (Loss), Net of Tax	1,341	2,549	8,358
Accumulated other comprehensive income (loss), net of tax	-686	-2,027	-4,576
PUGET SOUND ENERGY, INC. | Comprehensive Income
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss), net of tax	-95,739	-187,198	-188,579
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	-84,955	74,969	-17,049
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	9,737	16,490	18,430
Other Comprehensive Income (Loss), Net of Tax	-75,218	91,459	1,381
Accumulated other comprehensive income (loss), net of tax	($170,957)	($95,739)	($187,198)

Accumulated_Other_Comprehensiv3

Accumulated Other Comprehensive Income (Loss) Reclassifications Out of Accumulated Other Comprehensive Income (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2012
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Interest Expense, Debt	($367,308)	($392,264)		($392,216)
Cost of Purchased Power	514,087	541,905		622,288
Comprehensive income (loss)	87,077	366,272		271,899
Interest Rate Contract | Interest Expense
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Interest Expense, Debt	-144	-4,505		-17,811
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	50	1,577		6,234
Comprehensive income (loss)	-94	-2,928		-11,577
Amortization of Prior Service Cost | Pension Cost
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	1,938	1,997	[1]	1,980	[1]
Amortization of Net Gain (Loss) | Pension Cost
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	-519	-4,420	[1]	-1,524	[1]
Qualified Pension Benefits | Pension Cost
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	1,419	-2,423		456
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	-496	848		-160
Comprehensive income (loss)	923	-1,575		296
Electric Derivative | Electric Generation Fuel
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	0	0		100
Electric Derivative | Purchased Electricity
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	-572	-57		-671
Electric Derivative | Electric Derivative, Total
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	-572	-57		-571
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	200	20		200
Comprehensive income (loss)	-372	-37		-371
Reclassification out of Accumulated Other Comprehensive Income
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Comprehensive income (loss)	457	-4,540		-11,652
PUGET SOUND ENERGY, INC.
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Interest Expense, Debt	-264,745	-261,264		-246,811
Cost of Purchased Power	514,087	541,905		622,288
Comprehensive income (loss)	161,396	447,588		357,551
PUGET SOUND ENERGY, INC. | Interest Rate Contract | Interest Expense
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Interest Expense, Debt	-488	-488		-488
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	171	171		171
Comprehensive income (loss)	-317	-317		-317
PUGET SOUND ENERGY, INC. | Amortization of Prior Service Cost | Pension Cost
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	1,526	1,559	[1]	1,245	[1]
PUGET SOUND ENERGY, INC. | Amortization of Net Gain (Loss) | Pension Cost
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	-13,954	-22,519	[1]	-16,203	[1]
PUGET SOUND ENERGY, INC. | Amortization of Transition Obligation | Pension Cost
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	0	0	[1]	-50	[1]
PUGET SOUND ENERGY, INC. | Qualified Pension Benefits | Pension Cost
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	-12,428	-20,960		-15,008
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	4,349	7,336		5,253
Comprehensive income (loss)	-8,079	-13,624		-9,755
PUGET SOUND ENERGY, INC. | Electric Derivative | Electric Generation Fuel
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	0	0		97
PUGET SOUND ENERGY, INC. | Electric Derivative | Purchased Electricity
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Cost of Purchased Power	-2,063	-3,922		-12,955
PUGET SOUND ENERGY, INC. | Electric Derivative | Electric Derivative, Total
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	-2,063	-3,922		-12,858
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	722	1,373		4,500
Comprehensive income (loss)	-1,341	-2,549		-8,358
PUGET SOUND ENERGY, INC. | Reclassification out of Accumulated Other Comprehensive Income
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Comprehensive income (loss)	($9,737)	($16,490)		($18,430)
[1]	These accumulated other comprehensive income components are included in the computation of net periodic pension cost (see Note 12 for additional details).

SUPPLEMENTAL_QUARTERLY_FINANCI2

SUPPLEMENTAL QUARTERLY FINANCIAL DATA (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Financial Information [Line Items]
Operating revenues	$831,165	$593,715	$662,916	$1,025,375	$946,645	$598,348	$642,486	$999,818	$3,113,171	$3,187,297	$3,215,156
Operating income	131,215	65,069	145,266	236,301	242,301	100,043	95,081	317,735	577,851	755,160	715,535
Net income (loss)	36,088	-12,958	41,113	107,592	108,808	8,540	905	167,475	171,835	285,728	273,821
PUGET SOUND ENERGY, INC.
Quarterly Financial Information [Line Items]
Operating revenues	833,881	593,951	662,916	1,025,375	946,794	598,348	642,486	999,707	3,116,123	3,187,335	3,216,259
Operating income	131,214	62,317	142,185	232,977	237,808	96,085	91,094	310,587	568,693	735,574	692,989
Net income (loss)	$54,640	$3,057	$57,834	$121,083	$122,923	$26,605	$26,663	$179,938	$236,614	$356,129	$356,170

SCHEDULE_I_CONDENSED_FINANCIAL1

SCHEDULE I CONDENSED FINANCIAL INFORMATION OF PUGET ENERGY - Condensed Statements of Income (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Non-utility expense and other									($13,109)	$3,555	($814)
Unhedged interest rate swap expense									-3,915	2,420	-4,288
Interest expense									-367,308	-392,264	-392,216
Income taxes									-56,985	-122,408	-104,725
Net income (loss)	36,088	-12,958	41,113	107,592	108,808	8,540	905	167,475	171,835	285,728	273,821
Comprehensive income (loss)									87,077	366,272	271,899
PUGET ENERGY
Condensed Financial Statements, Captions [Line Items]
Non-utility expense and other									-5,390	-1,255	-2,040
Equity In Net Income (Loss) Of Subsidiaries									240,102	351,718	365,590
Unhedged interest rate swap expense									-3,915	2,420	-4,288
Interest income									185	114	214
Interest expense									-93,382	-103,372	-135,312
Income taxes									34,235	36,103	49,657
Net income (loss)									171,835	285,728	273,821
Comprehensive income (loss)									$87,077	$366,272	$271,899

SCHEDULE_I_CONDENSED_FINANCIAL2

SCHEDULE I CONDENSED FINANCIAL INFORMATION OF PUGET ENERGY - Condensed Balance Sheets (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011	Feb. 06, 2009
In Thousands, unless otherwise specified
Other property and investments:
Goodwill	$1,656,513		$1,656,513				$1,700,000
Current assets:
Cash and Cash Equivalents, at Carrying Value	37,527		44,302		135,542	37,235
Deferred income taxes	161,445		86,004
Total current assets	966,719		1,007,190
Long-term assets:
Other	96,275		130,909
Total assets	12,835,048		12,906,575
Capitalization and liabilities:
Common equity	3,543,328		3,679,679		3,484,228	3,300,923
Long-term debt	1,699,000		1,699,000
Total capitalization	8,624,936		8,912,155
Current liabilities:
Accounts payable	307,578		296,681
Interest	78,914		79,303
Deferred income taxes	1,522,357		1,487,005
Unrealized loss on derivative instruments	142,195		48,049
Total current liabilities	990,496		804,293
Long-term liabilities:
Unrealized loss on derivative instruments	62,913		38,162
Total capitalization and liabilities	12,835,048		12,906,575
PUGET ENERGY
Assets:
Investments in subsidiaries	3,337,718		3,508,460
Other property and investments:
Goodwill	1,656,513		1,656,513
Current assets:
Cash and Cash Equivalents, at Carrying Value	62		191		12	6,224
Receivables from affiliates	28,950	[1]	29,605	[1]
Total current assets	29,012		29,796
Long-term assets:
Deferred income taxes	267,810		241,787
Other	15,802		17,992
Total long-term assets	283,612		259,779
Total assets	5,306,855		5,454,548
Capitalization and liabilities:
Common equity	3,543,328		3,679,679
Long-term debt	1,698,968		1,698,964
Total capitalization	5,242,296		5,378,643
Current liabilities:
Accounts payable	130		322
Interest	23,585		24,047
Deferred income taxes	31,772		38,296
Unrealized loss on derivative instruments	6,222		6,584
Total current liabilities	61,709		69,249
Long-term liabilities:
Unrealized loss on derivative instruments	2,850		6,656
Total long-term liabilities	2,850		6,656
Total capitalization and liabilities	$5,306,855		$5,454,548
[1]	Eliminated in consolidation.

SCHEDULE_I_CONDENSED_FINANCIAL3

SCHEDULE I CONDENSED FINANCIAL INFORMATION OF PUGET ENERGY - Condensed Statements of Cash Flows (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating activities:
Net income	$171,835	$285,728	$273,821
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Unrealized gain on derivative instruments	80,139	-106,540	-146,680
Deferred income taxes and tax credits - net	56,984	122,409	100,457
Taxes	-4	4,499	6,174
Accounts payable	9,098	4,597	-25,963
Net cash provided by operating activities	701,782	766,068	782,685
Investing activities:
Other	-4,512	-17,871	-38,923
Net cash used in investing activities	-395,162	-480,918	-692,970
Financing activities:
Dividends paid	-223,428	-170,821	-88,594
Long-term notes and bonds issued	299,000	161,860	1,314,000
Redemption of term-loan and other long-term debt	-299,000	-309,860	-1,273,000
Net cash provided by (used in) financing activities	-313,395	-376,390	8,592
Net increase (decrease) in cash and cash equivalents	-6,775	-91,240	98,307
Cash and cash equivalents at beginning of period	44,302	135,542	37,235
Cash and cash equivalents at end of period	37,527	44,302	135,542
PUGET ENERGY
Operating activities:
Net income	171,835	285,728	273,821
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Unrealized gain on derivative instruments	-4,024	-3,869	-12,984
Deferred income taxes and tax credits - net	-32,597	-35,872	-49,496
Equity in earnings of subsidiary	-240,102	-351,718	-365,590
Other	4,758	3,055	11,409
Dividends received from subsidiary	323,424	410,977	175,625
Accounts receivable	-10	3	283
Accounts payable	-192	110	212
Accrued interest	2,367	-1,299	33,842
Net cash provided by operating activities	225,459	307,115	67,122
Investing activities:
(Increase) decrease in loan to subsidiary	-665	0	-400
Other	-2,829	-1,120	-20,901
Net cash used in investing activities	-2,164	-1,120	-20,501
Financing activities:
Dividends paid	-223,428	-170,821	-88,594
Long-term notes and bonds issued	0	0	884,000
Redemption of term-loan and other long-term debt	0	-135,000	-843,000
Issue costs and others	4	5	-5,239
Net cash provided by (used in) financing activities	-223,424	-305,816	-52,833
Net increase (decrease) in cash and cash equivalents	-129	179	-6,212
Cash and cash equivalents at beginning of period	191	12	6,224
Cash and cash equivalents at end of period	$62	$191	$12

SCHEDULE_I_CONDENSED_FINANCIAL4

SCHEDULE I CONDENSED FINANCIAL INFORMATION OF PUGET ENERGY Notes (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Net income	$36,088,000	($12,958,000)	$41,113,000	$107,592,000	$108,808,000	$8,540,000	$905,000	$167,475,000	$171,835,000	$285,728,000	$273,821,000
Goodwill, Purchase Accounting Adjustments									3,500,000	-4,400,000	9,400,000
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									87,077,000	366,272,000	271,899,000
Net Cash Provided by (Used in) Operating Activities									701,782,000	766,068,000	782,685,000
Net Cash Provided by (Used in) Investing Activities									-395,162,000	-480,918,000	-692,970,000
PUGET ENERGY
Net income									171,835,000	285,728,000	273,821,000
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									87,077,000	366,272,000	271,899,000
Net Cash Provided by (Used in) Operating Activities									225,459,000	307,115,000	67,122,000
Net Cash Provided by (Used in) Investing Activities									-2,164,000	-1,120,000	-20,501,000
PUGET SOUND ENERGY, INC.
Net income	54,640,000	3,057,000	57,834,000	121,083,000	122,923,000	26,605,000	26,663,000	179,938,000	236,614,000	356,129,000	356,170,000
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									161,396,000	447,588,000	357,551,000
Net Cash Provided by (Used in) Operating Activities									782,727,000	835,679,000	797,882,000
Net Cash Provided by (Used in) Investing Activities									($392,333,000)	($479,798,000)	($672,069,000)

SCHEDULE_II_VALUATION_AND_QUAL1

SCHEDULE II VALUATION AND QUALIFYING ACCOUNTS AND RESERVES (Details) (Allowance for doubtful accounts receivable, USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance At Beginning of Period	$7,385	$9,932	$8,495
Additions Charged to Costs and Expenses	27,228	26,330	21,567
Deductions	27,141	28,877	20,130
Balance At End Of Period	7,472	7,385	9,932
PUGET SOUND ENERGY, INC.
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance At Beginning of Period	7,385	9,932	8,495
Additions Charged to Costs and Expenses	27,228	26,330	21,567
Deductions	27,141	28,877	20,130
Balance At End Of Period	$7,472	$7,385	$9,932