Derivative Financial Instruments and Risk Management (Details) $ in Millions	12 Months Ended
Dec. 31, 2016 USD ($)
Derivative
Deferred gains on liquidated interest rate contracts	$ 32
Maximum
Derivative
Deferred net gains, interest rate risk, to be reclassified from equity to current earnings over the next twelve months	$ 1

The estimated net amount of unrealized gains or losses on interest rate cash flow hedges as of the balance sheet date expected to be reclassified to earnings within the next twelve months.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80748-113994

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant