Postretirement Benefit Plans (Future Benefit Payments) (Details) $ in Millions	Dec. 31, 2020 USD ($)
Pension
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block
2018	$ 38
2019	39
2020	40
2021	40
2022	42
Years 2022-2026	220
Other Benefits
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block
2018	3
2019	3
2020	3
2021	3
2022	3
Years 2022-2026	$ 12

Amount of benefit for defined benefit plan expected to be paid in five fiscal years after fifth fiscal year following current fiscal year.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

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Amount of benefit for defined benefit plan expected to be paid in next fiscal year following current fiscal year.

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Amount of benefit for defined benefit plan expected to be paid in fifth fiscal year following current fiscal year.

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Amount of benefit for defined benefit plan expected to be paid in fourth fiscal year following current fiscal year.

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Amount of benefit for defined benefit plan expected to be paid in third fiscal year following current fiscal year.

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Amount of benefit for defined benefit plan expected to be paid in second fiscal year following current fiscal year.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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