Accumulated Other Comprehensive Income/(Loss) (Details 2) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other income (expense)		$ (5)	$ (2)	$ (12)	$ (6)
Interest		(190)	(168)	(364)	(330)
Reclassifications before tax		100	164	224	331
Tax (provision) benefit		(24)	(49)	(53)	(99)
Total reclassifications from Accumulated other comprehensive income/(loss)	[1]	71	114	162	229
Reclassifications out of Accumulated other comprehensive income/(loss) | Derivative financial instruments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications before tax		124	(25)	99	(46)
Tax (provision) benefit		(28)	9	(23)	16
Total reclassifications from Accumulated other comprehensive income/(loss)		96	(16)	76	(30)
Reclassifications out of Accumulated other comprehensive income/(loss) | Derivative financial instruments | Cross currency contracts
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other income (expense)		119	(27)	90	(49)
Interest		5	0	8	0
Reclassifications out of Accumulated other comprehensive income/(loss) | Derivative financial instruments | Interest rate contracts
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest		$ 0	$ 2	$ 1	$ 3

[1] Profit attributable to Caterpillar Financial Services Corporation.