Reserves for Losses (Details 2) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance			$ 573,000,000	$ 521,000,000
Provisions	$ 238,000,000	$ 214,000,000	715,000,000	701,000,000
Net write-offs			(657,000,000)	(661,000,000)
Other			(16,000,000)	(17,000,000)
Ending balance	$ 615,000,000	$ 544,000,000	615,000,000	544,000,000
Recoveries			278,000,000	273,000,000
Troubled Debt Restructuring [Member]
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Net write-offs			(11,000,000)
Recoveries				1,000,000
Foreign Currency Translation Adjustments [Member]
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Other			(3,000,000)	0
Other Items [Member]
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Other			$ (13,000,000)	$ (17,000,000)