Customer Financing (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Customer Financing [Line Items]
Operating lease incentive	$ 250
Individually evaluated for impairment	409	$ 422
Impaired financing receivables	398	$ 411
Average recorded investment in impaired receivables	$ 403
B Credit Rating [Member]
Customer Financing [Line Items]
Percentage Of Credit Default Rates Applied To Customers	22.80%
BB Credit Rating [Member]
Customer Financing [Line Items]
Percentage Of Credit Default Rates Applied To Customers	6.50%
BBB Credit Rating [Member]
Customer Financing [Line Items]
Percentage Of Credit Default Rates Applied To Customers	0.70%