Revenue (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Operating-type lease and sales-type lease, revenues	$ 432	$ 401
Revenue, remaining performance obligation	$ 2,000
Revenue, remaining performance obligation, expected satisfaction in the next 12 months, percent	41.00%
Revenue, remaining performance obligation, expected satisfaction in year two, percent	26.00%
Contract with customer, asset, net	$ 77	82
Contract with customer, liability	806	737
Contract with customer, liability, revenue recognized	$ 603	$ 597