Revenue from Contracts with Customers - Contract Costs (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Capitalized Contract Cost [Abstract]
Deferred incremental costs to obtain contracts	$ 906,000,000	$ 644,000,000
Average amortization period, deferred contract costs (in months)	24 months
Amortization of deferred costs	$ 604,000,000	267,000,000
Impairment losses recognized on deferred contract cost assets	$ 0	$ 0