Long-term Customer Financing and Sales Of Receivables (Credit Quality Of Customer Financing Receivables And Allowance For Credit Losses) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Total Long-term Receivable	$ 49	$ 27
Current Billed Due		10
Past Due Under 90 Days		2
Past Due Over 90 Days	12	10
Municipal leases secured tax exempt
Debt Instrument [Line Items]
Total Long-term Receivable	14	1
Current Billed Due		0
Past Due Under 90 Days		0
Past Due Over 90 Days	0	0
Commercial loans and leases secured
Debt Instrument [Line Items]
Total Long-term Receivable	35	26
Current Billed Due		10
Past Due Under 90 Days		2
Past Due Over 90 Days	$ 12	$ 10