[Line Items] for Notional Amount of Outstanding Derivative Contracts [Table]

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- Definition

Nominal number of units used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959

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- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

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Derivative Instruments - Notional Amounts of Outstanding Derivative Instruments (Details) ¥ in Millions, $ in Millions, $ in Millions	Sep. 30, 2019 USD ($) MW	Sep. 30, 2019 CAD ($) MW	Sep. 30, 2019 JPY (¥) MW	Dec. 31, 2018 USD ($) MW	Dec. 31, 2018 CAD ($) MW	Dec. 31, 2018 JPY (¥) MW	Dec. 31, 2010 MW
Interest rate swaps \| Designated Derivative Instruments
Notional Amount of Outstanding Derivative Contracts [Line Items]
Notional amount	$ 346	$ 707	¥ 54,987	$ 319	$ 721	¥ 55,675
Interest rate swaps \| Undesignated Derivative Instruments
Notional Amount of Outstanding Derivative Contracts [Line Items]
Notional amount \| $	$ 0			$ 138
Energy derivative \| Undesignated Derivative Instruments
Notional Amount of Outstanding Derivative Contracts [Line Items]
Nonmonetary notional amount	0	0	0	193,252	193,252	193,252	504,220
Foreign currency forward contracts \| Undesignated Derivative Instruments
Notional Amount of Outstanding Derivative Contracts [Line Items]
Notional amount		$ 77	¥ 10,691		$ 106	¥ 11,589
Congestion revenue rights \| Undesignated Derivative Instruments
Notional Amount of Outstanding Derivative Contracts [Line Items]
Nonmonetary notional amount	248	248	248	505	505	505