Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) $ in Millions		Jun. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)
Contingent consideration [Member] | Fair Value Inputs, Discount Rate [Member]
Liabilities:
Fair value inputs, weighted-average discount rate		9.03	10.16
Contingent consideration [Member] | Fair Value Inputs, Discount Rate [Member] | Minimum [Member]
Liabilities:
Fair value inputs, weighted-average discount rate		3.53
Contingent consideration [Member] | Fair Value Inputs, Discount Rate [Member] | Maximum [Member]
Liabilities:
Fair value inputs, weighted-average discount rate		13.00
Recurring [Member]
Assets:
Mutual funds / exchange traded funds		$ 7	$ 20
Derivative financial instruments	[1]	3	32
Liabilities:
Contingent consideration	[2]	22	17
Derivative financial instruments	[1]	18	3
Recurring [Member] | Level 1 [Member]
Assets:
Mutual funds / exchange traded funds		7	20
Derivative financial instruments	[1]	0	0
Liabilities:
Contingent consideration	[2]	0	0
Derivative financial instruments	[1]	0	0
Recurring [Member] | Level 2 [Member]
Assets:
Mutual funds / exchange traded funds		0	0
Derivative financial instruments	[1]	3	32
Liabilities:
Contingent consideration	[2]	0	0
Derivative financial instruments	[1]	18	3
Recurring [Member] | Level 3 [Member]
Assets:
Mutual funds / exchange traded funds		0	0
Derivative financial instruments	[1]	0	0
Liabilities:
Contingent consideration	[2]	22	17
Derivative financial instruments	[1]	$ 0	$ 0

[1] See Note 8 — Derivative Financial Instruments for further information on our derivative investments.

[2] Probability weightings are based on our knowledge of the past and planned performance of the acquired entity to which the contingent consideration applies. The fair value weighted-average discount rates used on our material contingent consideration calculations were 9.03% and 10.16% at June 30, 2020 and December 31, 2019, respectively. The range of these discount rates was 3.53% - 13.00% at June 30, 2020. Using different probability weightings and discount rates could result in an increase or decrease of the contingent consideration payable.