Financing Receivables: (Details 7) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due (> 90 days)	$ 68	$ 82
Current	21,612	22,428
Total Financing Receivables	21,681	22,510
Recorded Investment > 90 Days and Accruing	44	52
Troubled debt restructurings of financing receivables	0	0
Major Markets
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Financing Receivables	15,747	16,701
Growth Markets
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Financing Receivables	5,934	5,808
Lease receivables
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due (> 90 days)	25	20
Current	8,785	9,154
Total Financing Receivables	8,809	9,174
Recorded Investment > 90 Days and Accruing	20	13
Lease receivables | Major Markets
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due (> 90 days)	9	8
Current	6,696	7,028
Total Financing Receivables	6,705	7,036
Recorded Investment > 90 Days and Accruing	9	5
Lease receivables | Growth Markets
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due (> 90 days)	16	11
Current	2,089	2,127
Total Financing Receivables	2,104	2,138
Recorded Investment > 90 Days and Accruing	11	8
Loan receivables
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due (> 90 days)	43	63
Current	12,828	13,273
Total Financing Receivables	12,871	13,336
Recorded Investment > 90 Days and Accruing	24	39
Loan receivables | Major Markets
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due (> 90 days)	15	27
Current	9,027	9,639
Total Financing Receivables	9,042	9,666
Recorded Investment > 90 Days and Accruing	14	8
Loan receivables | Growth Markets
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due (> 90 days)	29	36
Current	3,801	3,634
Total Financing Receivables	3,830	3,670
Recorded Investment > 90 Days and Accruing	$ 10	$ 31