New Accounting Pronouncements (Narrative) (Details) $ in Millions	9 Months Ended
Sep. 30, 2017 USD ($)
New Accounting Pronouncements [Abstract]
Net cumulative-effect adjustment	$ 59

Amount of the cumulative effect on retained earnings net of related income tax effect.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=64853466&loc=d3e22663-107794

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