Derivative Instruments and Hedging Activities (Fair Value Of Derivatives Designated As Hedging Instruments) (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Interest Rate Derivative Assets, at Fair Value	$ 6
Interest Rate Derivative Liabilities, at Fair Value	0
Designated As Hedging Instrument [Member]
Derivative [Line Items]
Interest Rate Derivative Assets, at Fair Value	6	$ 11
Interest Rate Derivative Liabilities, at Fair Value		0
Derivative Instruments in Hedges, Assets, at Fair Value	6	11
Derivative Instruments in Hedges, Liabilities, at Fair Value	$ 0	$ 0

Aggregate fair value of all derivative assets designated as hedging instruments. Includes instruments designated as cash flow hedges, fair value hedges, and hedges of net investments in foreign operations.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13433-108611

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- Definition

Aggregate fair value of all derivative liabilities designated as hedging instruments. Includes instruments designated as cash flow hedges, fair value hedges, and hedges of net investments in foreign operations.

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- Definition

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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- Definition

Fair value as of the balance sheet date of interest rate derivative assets, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as assets.

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- Definition

Fair value as of the balance sheet date of interest rate derivative liabilities, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as liabilities.

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