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Other Postretirement Benefits - Schedule of Change of Assumed Health Care Cost Trend Rate (Details) - Other Postretirement Benefits $ in Millions | 12 Months Ended
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Dec. 31, 2019 USD ($)
Increase |
Effect on accumulated other postretirement benefit obligation | $ 60
Effect on service cost and interest cost components for 2019 | 1
Decrease |
Effect on accumulated other postretirement benefit obligation | (17)
Effect on service cost and interest cost components for 2019 | 0
CECONY |
Increase |
Effect on accumulated other postretirement benefit obligation | 33
Effect on service cost and interest cost components for 2019 | (1)
Decrease |
Effect on accumulated other postretirement benefit obligation | 3
Effect on service cost and interest cost components for 2019 | $ 2

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