Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) $ in Millions	Sep. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)
Contingent consideration [Member] \| Fair Value Inputs, Discount Rate [Member]
Liabilities:
Fair Value Inputs, Discount Rate	9.88	9.64
Recurring [Member]
Assets:
Mutual funds / exchange traded funds	$ 19	$ 40
Derivative financial instruments	3	18
Liabilities:
Contingent consideration	49	51
Derivative financial instruments	15	37
Recurring [Member] \| Level 1 [Member]
Assets:
Mutual funds / exchange traded funds	19	40
Derivative financial instruments	0	0
Liabilities:
Contingent consideration	0	0
Derivative financial instruments	0	0
Recurring [Member] \| Level 2 [Member]
Assets:
Mutual funds / exchange traded funds	0	0
Derivative financial instruments	3	18
Liabilities:
Contingent consideration	0	0
Derivative financial instruments	15	37
Recurring [Member] \| Level 3 [Member]
Assets:
Mutual funds / exchange traded funds	0	0
Derivative financial instruments	0	0
Liabilities:
Contingent consideration	49	51
Derivative financial instruments	$ 0	$ 0

Value of input used to measure alternative investment.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
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-Section 50
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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value of obligations measured on a recurring basis.

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