XML 168 R161.htm IDEA: XBRL DOCUMENT v3.6.0.2

Fair Value Measurements and Financial Instruments - Volume of Derivative Activity (Details) - Not designated as hedging instrument kJ in Trillions	12 Months Ended
	Dec. 31, 2016 GWh kJ contract
Electricity swap contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of contracts | contract	8
Electricity swap contracts, 2017
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj) | GWh	1,089
Electricity swap contracts, 2018
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj) | GWh	657
Electricity swap contracts, 2019
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj) | GWh	438
Electricity swap contracts, 2020
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj) | GWh	0
Electricity swap contracts, 2021
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj) | GWh	0
Electricity swap contracts thereafter
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj) | GWh	0
Electricity power purchase contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of contracts | contract	39
Electricity power purchase contracts, 2017
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj) | GWh	1,252
Electricity power purchase contracts, 2018
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj) | GWh	0
Electricity power purchase contracts, 2019
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj) | GWh	0
Electricity power purchase contracts, 2020
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj) | GWh	0
Electricity power purchase contracts, 2021
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj) | GWh	0
Electricity power purchase contracts, thereafter
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj) | GWh	0
Gas swap and option contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of contracts | contract	108
Gas swap and option contracts, 2017
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj)	20
Gas swap and option contracts, 2018
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj)	11
Gas swap and option contracts, 2019
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj)	4
Gas swap and option contracts, 2020
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj)	0
Gas swap and option contracts, 2021
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj)	0
Gas swap and option contracts, thereafter
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj)	0
Gas supply contract premiums, subject to regulatory deferral
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of contracts | contract	85
Gas supply contract premiums, subject to regulatory deferral, 2017
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj)	82
Gas supply contract premiums, subject to regulatory deferral, 2018
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj)	45
Gas supply contract premiums, subject to regulatory deferral, 2019
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj)	26
Gas supply contract premiums, subject to regulatory deferral, 2020
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj)	22
Gas supply contract premiums, subject to regulatory deferral, 2021
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj)	22
Gas supply contract premiums, subject to regulatory deferral, thereafter
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj)	43
Long-term wholesale trading contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of contracts | contract	18
Long-term wholesale trading contracts, 2017
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj) | GWh	2,058
Long-term wholesale trading contracts, 2018
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj) | GWh	0
Long-term wholesale trading contracts, 2019
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj) | GWh	0
Long-term wholesale trading contracts, 2020
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj) | GWh	0
Long-term wholesale trading contracts, 2021
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj) | GWh	0
Long-term wholesale trading contracts, thereafter
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj) | GWh	0
Gas supply contract premiums, not subject to regulatory deferral
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of contracts | contract	226
Gas supply contract premiums, not subject to regulatory deferral, 2017
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj)	15
Gas supply contract premiums, not subject to regulatory deferral, 2018
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj)	0
Gas supply contract premiums, not subject to regulatory deferral, 2019
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj)	0
Gas supply contract premiums, not subject to regulatory deferral, 2020
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj)	0
Gas supply contract premiums, not subject to regulatory deferral, 2021
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj)	0
Gas supply contract premiums, not subject to regulatory deferral, thereafter
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj)	0
Gas swap contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of contracts | contract	7
Gas swap contracts, not subject to regulatory deferral, 2017
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj)	4
Gas swap contracts, not subject to regulatory deferral, 2018
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj)	0
Gas swap contracts, not subject to regulatory deferral, 2019
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj)	0
Gas swap contracts, not subject to regulatory deferral, 2020
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj)	0
Gas swap contracts, not subject to regulatory deferral, 2021
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj)	0
Gas swap contracts, not subject to regulatory deferral, thereafter
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (gwh / kj)	0

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5579245-113959

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