Income Taxes - Tax Examinations (Details) (Internal Revenue Service (IRS) [Member], USD $) In Millions, unless otherwise specified	Sep. 30, 2013
Internal Revenue Service (IRS) [Member]
Income Tax Examination [Line Items]
(Increase) decrease to shareholder's net income resulting from IRS examination	$ (18)
Increase (decrease) to income tax expense resulting from IRS examination	(19)
Pre-tax gain (charge) resulting from IRS examination	$ (1)

The amount of the additional liability or refund received or expected based on a final settlement with a taxing authority.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319

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