Credit Losses on Financial Instruments (Details) $ in Millions	3 Months Ended
	Mar. 31, 2020 USD ($)
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance at January 1, 2020	$ 35
Current period provision for expected losses	13
Write-offs charged against the allowance	(16)
Recoveries collected	5
Ending Balance at March 31, 2020	$ 37