Leases Reconciliation of Undiscounted Cash Flows (Details) $ in Millions	Mar. 31, 2019 USD ($)
Lessee, Lease, Description [Line Items]
Total Minimum Lease Payments	$ 364
Reconciling Amount due to Discount Rate	(89)
Total Discounted Operating Lease Liabilities	275
Pse And G
Lessee, Lease, Description [Line Items]
Total Minimum Lease Payments	115
Reconciling Amount due to Discount Rate	(25)
Total Discounted Operating Lease Liabilities	90
Power
Lessee, Lease, Description [Line Items]
Total Minimum Lease Payments	70
Reconciling Amount due to Discount Rate	(27)
Total Discounted Operating Lease Liabilities	43
Other
Lessee, Lease, Description [Line Items]
Total Minimum Lease Payments	179
Reconciling Amount due to Discount Rate	(37)
Total Discounted Operating Lease Liabilities	$ 142