Finance Assets, net (Schedule of Allowance for Losses on Finance Assets) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	$ 42	$ 52
(Decrease) increase to allowance	0	(10)
Ending balance	$ 42	$ 42

The increase (decrease) in the allowance for credit losses related to financing receivables.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953423-111524

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesPeriodIncreaseDecrease
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration