Nature of Operations and Summary of Significant Accounting Policies - Contract Assets, Receivables, and Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Revenues	$ 3,089	$ 1,199	$ 5,554	$ 2,546
Trade receivables before allowance for credit loss	2,101		$ 2,101		$ 950
Percentage of outstanding receivables less than 90 days			90.00%
Trade receivables (net of allowances of $42 and $21, respectively)	$ 2,059		$ 2,059		$ 929