Credit Losses on Financial Instruments (Details) $ in Millions	6 Months Ended
	Jun. 30, 2020 USD ($)
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance at January 1, 2020	$ 35
Provision for expected losses	31
Write-offs charged against the allowance	(30)
Recoveries collected	6
Ending Balance at June 30, 2020	42
Business
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance at January 1, 2020	17
Provision for expected losses	17
Write-offs charged against the allowance	(12)
Recoveries collected	2
Ending Balance at June 30, 2020	24
Consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance at January 1, 2020	18
Provision for expected losses	14
Write-offs charged against the allowance	(18)
Recoveries collected	4
Ending Balance at June 30, 2020	$ 18