Nature of Operations and Basis of Presentation - Narrative (Details) $ in Millions	9 Months Ended
	Sep. 30, 2020 USD ($) Segment	Dec. 31, 2019 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of reportable segments | Segment	4
Restricted cash	$ 20	$ 20
Contract asset	33	28
Unearned revenue	1,700
Revenue expected to be recognized as of period end	2,000
Capitalized contract costs	$ 112	$ 115
Amortization period of capitalized contract cost	5 years
Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Period of recognition for remaining performance obligation	12 months
Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Period of recognition for remaining performance obligation	24 months