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Derivative Instruments and Hedging Activities - Additional Information (Details) $ in Millions | 6 Months Ended
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Jun. 30, 2020 USD ($)
Investment Holdings [Line Items] |
Energy supply and hedging activities credit exposure total | $ 222
Makeup of net credit exposure non-investment grade/non-rated counterparties | 57
Makeup of net credit exposure independent system operators | 94
Makeup of net credit exposure with investment-grade counterparties | 57
Makeup of net credit exposure with commodity exchange brokers | 14
CECONY |
Investment Holdings [Line Items] |
Energy supply and hedging activities credit exposure total | 19
Makeup of net credit exposure with investment-grade counterparties | 9
Makeup of net credit exposure with commodity exchange brokers | $ 10

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