Commitments: (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 Extended lines of credit	Dec. 31, 2012 Extended lines of credit	Jun. 30, 2013 Financing for client purchase agreements	Dec. 31, 2012 Financing for client purchase agreements	Jun. 30, 2013 Financial guarantees	Dec. 31, 2012 Financial guarantees
Commitments, guarantees:
Unused amounts in lines of credit to third-party entities and commitments for future financing to clients			$ 4,889	$ 4,719	$ 1,566	$ 1,513
Guarantor obligations, maximum exposure							58	65
Movement in standard warranty liability
Beginning Balance	394	407
Current period accruals	163	181
Accrual adjustments to reflect actual experience	11	(9)
Charges incurred	(192)	(199)
Ending Balance	$ 376	$ 380