Fair Value

Financial assets and liabilities measured at fair value on a recurring basis at December 31, 2017 and 2016 were (in millions):



2017	Level 1		Level 2		Level 3		Total
Assets:
Cash and cash equivalents	$	3,796.0					$	3,796.0
Short-term investments	0.4						0.4
Available-for-sale securities	1.4						1.4
Foreign currency derivatives			$	1.0			1.0
Liabilities:
Interest rate and foreign currency derivatives			$	39.5			$	39.5
Contingent purchase price obligations					$	215.6	215.6



2016
Assets:
Cash and cash equivalents	$	3,002.2					$	3,002.2
Short-term investments	20.6						20.6
Available-for-sale securities	4.3						4.3
Foreign currency derivatives			$	0.2			0.2
Liabilities:
Interest rate and foreign currency derivatives			$	48.9			$	48.9
Contingent purchase price obligations					$	386.1	386.1

Changes in contingent purchase price obligations for the years ended December 31, 2017 and 2016 were (in millions):



	2017			2016
January 1	$	386.1		$	322.0
Acquisitions	31.9			165.3
Revaluation and interest	(27.4		)	18.0
Payments	(187.0		)	(103.7		)
Foreign currency translation	12.0			(15.5		)
December 31	$	215.6		$	386.1

The carrying amount and fair value of our financial assets and liabilities at December 31, 2017 and 2016 were (in millions):



	2017				2016
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Assets:
Cash and cash equivalents	$	3,796.0	$	3,796.0	$	3,002.2	$	3,002.2
Short-term investments	0.4		0.4		20.6		20.6
Available-for-sale securities	1.4		1.4		4.3		4.3
Foreign currency derivatives	1.0		1.0		0.2		0.2
Cost method investments	14.4		14.4		14.2		14.2
Liabilities:
Short-term debt	$	11.8	$	11.8	$	28.7	$	28.7
Interest rate and foreign currency derivatives	39.5		39.5		48.9		48.9
Contingent purchase price obligations	215.6		215.6		386.1		386.1
Long-term debt, including current portion	4,912.9		5,056.9		4,920.6		5,035.1

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 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 long-term debt is based on quoted market prices.