Finance Receivables, Net - Summary (Details) - USD ($) $ in Millions		3 Months Ended						9 Months Ended	12 Months Ended
		Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Allowance for Credit Loss [Line Items]
Gross receivables		$ 3,600						$ 3,600	$ 3,865
Unearned income		(382)						(382)	(425)
Subtotal		3,218						3,218	3,440
Residual values		0						0	0
Allowance for doubtful accounts		(142)	$ (143)	$ (146)	$ (93)	$ (93)	$ (93)	(142)	(89)	$ (92)
Finance receivables, net		3,076						3,076	3,351
Less: Billed portion of finance receivables, net		111						111	111
Less: Current portion of finance receivables not billed, net		1,066						1,066	1,158
Finance receivables due after one year, net	[1]	1,899						$ 1,899	$ 2,082
Finance receivables lease portfolio -low - years								2 years
Finance lease portfolio average maturity - high - years								3 years
Charge-offs		(13)	(8)	(8)	(9)	(11)	(8)
Credit Concentration Risk | Financing Receivable
Financing Receivable, Allowance for Credit Loss [Line Items]
Concentration risk (percentage)								4.40%	2.60%
Europe
Financing Receivable, Allowance for Credit Loss [Line Items]
Subtotal		1,115						$ 1,115	$ 1,192
Allowance for doubtful accounts		(38)	(38)	(40)	(27)	(28)	(28)	$ (38)	$ (19)	$ (27)
Charge-offs		$ (5)	$ (2)	$ (4)	$ (3)	$ (3)	$ (3)

[1] Allowances at September 30, 2020 determined in accordance with ASU 2016-13 adopted effective January 1, 2020 - refer to Notes 2, 8 and 9 for additional information.