Acquisitions - Acquisitions (Details) (USD $) In Millions, unless otherwise specified			3 Months Ended		6 Months Ended		3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014 Digital Insight [Member]	Mar. 31, 2013 Digital Insight [Member]	Mar. 31, 2014 Digital Insight [Member]	Jan. 10, 2014 Digital Insight [Member]	Mar. 31, 2014 Digital Insight [Member] Customer Relationships [Member]	Mar. 31, 2014 Digital Insight [Member] Technology Software and Hardware [Member]	Mar. 31, 2014 Digital Insight [Member] Customer Contracts [Member]	Mar. 31, 2014 Digital Insight [Member] Trademarks [Member]	Mar. 31, 2014 Digital Insight [Member] Selling, General and Administrative Expenses [Member]
Business Acqusition, Pro Forma Information [Line Items]
Business Acquisition, Pro Forma Revenue			$ 1,526	$ 1,493
Business Acquisition, Pro Forma Net Income (Loss)			53	46
Business Acquisition, Pro Forma Expenses, Incremental Amortization Changes Attributable to Acquiree				7
Business Acquisition, Pro Forma Expenses, Incremental Interest Charges Attributable to Acquiree				13
Business Acquisitions, Pro Forma Expenses, Elimination of Transactions Costs			8	6
Business Acquisition [Line Items]
Business Acquisition, Goodwill, Expected Tax Deductible Amount						0
Business Acqusition, Purchase Price Allocation, Other Tangible Assets						74
Goodwill	2,789	1,534				1,255
Business Acquisition, Purchase Price Allocation, Amortizable Intangible Assets						559
Finite-lived Intangible Assets Acquired			559				336	121	89	13
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			13 years				18 years	5 years	8 years	7 years
Business Combination, Acquisition Related Costs					15						8
Deferred tax liabilities						(194)
Liabilities assumed						(46)
Total purchase consideration						1,648
Business Combination, Amount Withheld For Recovery of Possible Future Claims			$ 5