Employee Benefit Plans (Reconciliation of Assets Measured at Fair Value on a Recurring Basis) (Details) - Level 3 [Member] - USD ($) $ in Millions |
12 Months Ended | |
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Dec. 31, 2018 |
Dec. 31, 2017 |
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Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward] | ||
Plan assets at prior measurement date | $ 28 | $ 38 |
Sales | (1) | (2) |
Total gains (losses) and other, net | 0 | 1 |
Transfer of Level 3 assets to other classifications | 0 | (9) |
Plan assets at measurement date | $ 27 | 28 |
Piedmont Natural Gas [Member] | ||
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward] | ||
Plan assets at prior measurement date | $ 9 |
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- Definition Amount of increase (decrease) in plan assets of defined benefit plan from actual return (loss) determined by change in fair value of plan assets adjusted for contributions, benefit payments, and other expenses. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
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- Definition Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount, measured using unobservable input, of increase (decrease) in plan asset of defined benefit plan from purchase, sale and settlement of trade associated with underlying investment. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount, measured using unobservable inputs, of increase (decrease) in plan assets of defined benefit plan, for assets transferred into (out of) Level 3 of fair value hierarchy. Includes, but is not limited to, transfer due to change in observability of significant inputs. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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