Retrospective Responsibility Plan Changes in the Escrow Account (Details) (USD $) In Millions, unless otherwise specified	0 Months Ended	9 Months Ended				12 Months Ended
	Jan. 27, 2014	Jun. 30, 2014		Jun. 30, 2013		Sep. 30, 2013
Escrow Account [Roll Forward]
Litigation Escrow Account Balance, Beginning of Period		$ 49		$ 4,432		$ 4,432
Return of takedown payments to the litigation escrow account		1,056		0
Litigation Escrow Account Balance, End of Period		1,105
Class plaintiffs
Restricted Cash and Cash Equivalents Items [Line Items]
Adjustment to payments for litigation	1,100
Escrow Account [Roll Forward]
Payments to Settlement Funds		0	[1]	(4,033)	[1]	(4,033)
Individual Plaintiffs
Escrow Account [Roll Forward]
Payments to Settlement Funds		$ 0	[1]	$ (350)	[1]

[1] Payments made in fiscal 2013 are associated with the interchange multidistrict litigation. See Note 13—Legal Matters.