Financing Receivables: (Details 3) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Receivables	$ 172	$ 139
Lease receivables
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Receivables	45	47
Lease receivables | Major Markets
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Receivables	21	27
Lease receivables | Growth Markets
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Receivables	24	21
Loan receivables
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Receivables	127	92
Loan receivables | Major Markets
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Receivables	48	67
Loan receivables | Growth Markets
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Receivables	$ 79	$ 25