Fair Value

Financial assets and liabilities measured at fair value on a recurring basis at September 30, 2018 and December 31, 2017 were (in millions):



2018	Level 1		Level 2		Level 3		Total
Assets:
Cash and cash equivalents	$	2,099.1					$	2,099.1
Short-term investments	6.7						6.7
Investment in equity securities	1.6						1.6
Foreign currency derivative instruments			$	0.3			0.3
Liabilities:
Interest rate and foreign currency derivative instruments			$	83.5			$	83.5
Contingent purchase price obligations					$	225.0	225.0



2017
Assets:
Cash and cash equivalents	$	3,796.0					$	3,796.0
Short-term investments	0.4						0.4
Investment in equity securities	1.4						1.4
Foreign currency derivative instruments			$	1.0			1.0
Liabilities:
Interest rate and foreign currency derivative instruments			$	39.5			$	39.5
Contingent purchase price obligations					$	215.6	215.6

Changes in contingent purchase price obligations for the nine months ended September 30, 2018 and 2017 were (in millions):



	2018			2017
January 1	$	215.6		$	386.1
Acquisitions	84.1			41.7
Revaluation and interest	8.7			0.2
Payments	(66.4		)	(182.9		)
Foreign currency translation	(17.0		)	15.9
September 30	$	225.0		$	261.0

The carrying amount and fair value of our financial assets and liabilities at September 30, 2018 and December 31, 2017 were (in millions):



	2018				2017
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Assets:
Cash and cash equivalents	$	2,099.1	$	2,099.1	$	3,796.0	$	3,796.0
Short-term investments	6.7		6.7		0.4		0.4
Investment in equity securities	1.6		1.6		1.4		1.4
Foreign currency derivative instruments	0.3		0.3		1.0		1.0
Investment in equity securities without readily determinable fair value	11.8		11.8		14.4		14.4
Liabilities:
Short-term debt	$	11.3	$	11.3	$	11.8	$	11.8
Interest rate and foreign currency derivative instruments	83.5		83.5		39.5		39.5
Contingent purchase price obligations	225.0		225.0		215.6		215.6
Long-term debt, including current portion	4,857.2		4,840.3		4,912.9		5,056.9

The estimated fair value of the foreign currency and interest rate derivative instruments is determined using model-derived valuations, taking into consideration foreign currency rates for the foreign currency derivatives and readily observable inputs for LIBOR interest rates and yield curves to derive the present value of the future cash flows for the interest rate swap derivatives and counterparty credit risk for each. The estimated fair value of the contingent purchase price obligations is calculated in accordance with the terms of each acquisition agreement and is discounted. The fair value of debt is based on quoted market prices.