Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Carrying amount of goodwill
Balance at the beginning of the period	$ 784	$ 601
Acquisitions	5	186
Currency translation	14	(3)
Balance at the end of the period	803	784
Carrying value of goodwill and accumulated impairment charges
Goodwill before impairment charges	958	939
Accumulated impairment charges	(155)	(155)
Balance at the end of the period	803	784
North America
Carrying amount of goodwill
Balance at the beginning of the period	610	424
Acquisitions	(10)	186
Balance at the end of the period	600	610
Carrying value of goodwill and accumulated impairment charges
Goodwill before impairment charges	601	611
Accumulated impairment charges	(1)	(1)
Balance at the end of the period	600	610
South America
Carrying amount of goodwill
Balance at the beginning of the period	26	22
Currency translation		4
Balance at the end of the period	26	26
Carrying value of goodwill and accumulated impairment charges
Goodwill before impairment charges	59	59
Accumulated impairment charges	(33)	(33)
Balance at the end of the period	26	26
Asia Pacific
Carrying amount of goodwill
Balance at the beginning of the period	85	86
Acquisitions	15
Currency translation	7	(1)
Balance at the end of the period	107	85
Carrying value of goodwill and accumulated impairment charges
Goodwill before impairment charges	228	206
Accumulated impairment charges	(121)	(121)
Balance at the end of the period	107	85
EMEA
Carrying amount of goodwill
Balance at the beginning of the period	63	69
Currency translation	7	(6)
Balance at the end of the period	70	63
Carrying value of goodwill and accumulated impairment charges
Goodwill before impairment charges	70	63
Balance at the end of the period	$ 70	$ 63