Fair Value Measurements Carrying Value (Details) (Carrying Value [Member], USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
PUGET ENERGY [Member]
Assets:
Cash and Cash Equivalents	$ 16,133	$ 37,235
Restricted Cash	3,544	4,183
Notes Receivable and Other	65,883	73,031
Total assets	85,560	114,449
Liabilities:
Short-term Debt	38,000	25,000
Total liabilities	38,000	25,000
PUGET ENERGY [Member] | Level 1 [Member]
Assets:
Cash and Cash Equivalents	1,314	14,809
Restricted Cash	1,174	2,043
Notes Receivable and Other	0	0
Total assets	2,488	16,852
Liabilities:
Short-term Debt	0	0
Total liabilities	0	0
PUGET ENERGY [Member] | Level 2 [Member]
Assets:
Cash and Cash Equivalents	14,819	22,426
Restricted Cash	2,370	2,140
Notes Receivable and Other	65,883	73,031
Total assets	83,072	97,597
Liabilities:
Short-term Debt	38,000	25,000
Total liabilities	38,000	25,000
PUGET ENERGY [Member] | Level 3 [Member]
Assets:
Cash and Cash Equivalents	0	0
Restricted Cash	0	0
Notes Receivable and Other	0	0
Total assets	0	0
Liabilities:
Short-term Debt	0	0
Total liabilities	0	0
PUGET SOUND ENERGY, INC. [Member]
Assets:
Cash and Cash Equivalents	14,630	31,010
Restricted Cash	3,544	4,183
Notes Receivable and Other	65,883	73,031
Total assets	84,057	108,224
Liabilities:
Short-term Debt	38,000	25,000
Short-term Debt owed by PSE to PE	29,998	29,998
Total liabilities	67,998	54,998
PUGET SOUND ENERGY, INC. [Member] | Level 1 [Member]
Assets:
Cash and Cash Equivalents	200	9,200
Restricted Cash	1,174	2,043
Notes Receivable and Other	0	0
Total assets	1,374	11,243
Liabilities:
Short-term Debt	0	0
Short-term Debt owed by PSE to PE	0	0
Total liabilities	0	0
PUGET SOUND ENERGY, INC. [Member] | Level 2 [Member]
Assets:
Cash and Cash Equivalents	14,430	21,810
Restricted Cash	2,370	2,140
Notes Receivable and Other	65,883	73,031
Total assets	82,683	96,981
Liabilities:
Short-term Debt	38,000	25,000
Short-term Debt owed by PSE to PE	29,998	29,998
Total liabilities	67,998	54,998
PUGET SOUND ENERGY, INC. [Member] | Level 3 [Member]
Assets:
Cash and Cash Equivalents	0	0
Restricted Cash	0	0
Notes Receivable and Other	0
Total assets	0	0
Liabilities:
Short-term Debt	0	0
Short-term Debt owed by PSE to PE	0	0
Total liabilities	$ 0	$ 0