Goodwill and Other Intangible Assets (Goodwill Narrative) (Details) $ in Millions	12 Months Ended
Dec. 31, 2017 USD ($)
Goodwill [Line Items]
Goodwill, Impairment Loss	$ 387
Continuing Operations [Member]
Goodwill [Line Items]
Goodwill, Impairment Loss	$ 102

Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration