Pension and Other Postretirement Benefits, Estimated Future Benefit Payments (Details) $ in Millions	Dec. 31, 2018 USD ($)
Pension Plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2019	$ 168
2020	176
2021	184
2022	194
2023	201
Years 2024-2028	1,150
Postretirement Benefit Plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2019	12
2020	12
2021	12
2022	12
2023	12
Years 2024-2028	53
Subsidy Receipts, 2019	0
Subsidy Receipts, 2020	0
Subsidy Receipts, 2021	0
Subsidy Receipts, 2022	0
Subsidy Receipts, 2023	0
Subsidy Receipts, Years 2024-2028	$ 1

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