Revenues - Receivables (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Receivables for Product and Services in Accounts Receivable, Net	$ 884	$ 1,156
Equipment Receivables	43	85
Contract Assets	2	3
Contract Liabilities	34	$ 12
Revenue recognized that was included in the deferred revenue balance at the beginning of the period	$ 5