Fair Value

Financial assets and liabilities measured at fair value on a recurring basis at December 31, 2015 and 2014 were (in millions):



2015	Level 1		Level 2		Level 3		Total
Assets:
Cash and cash equivalents	$	2,605.2					$	2,605.2
Short-term investments	14.5						14.5
Available-for-sale securities	4.8						4.8
Interest rate and foreign currency derivative instruments			$	32.4			32.4
Liabilities:
Interest rate and foreign currency derivative instruments			$	15.9			$	15.9
Contingent purchase price obligations					$	322.0	322.0



2014
Assets:
Cash and cash equivalents	$	2,388.1					$	2,388.1
Short-term investments	2.2						2.2
Available-for-sale securities	4.9						4.9
Interest rate and foreign currency derivative instruments			$	43.1			43.1
Liabilities:
Foreign currency derivative instruments			$	0.4			$	0.4
Contingent purchase price obligations					$	300.7	300.7

The changes in contingent purchase price obligations for the years ended December 31, 2015 and 2014 were (in millions):



	2015			2014
January 1	$	300.7		$	220.2
Acquisitions	98.9			167.1
Revaluation and interest	21.8			11.0
Payments	(58.6		)	(83.2		)
Deferred payment	(21.4		)	—
Foreign currency translation	(19.4		)	(14.4		)
December 31	$	322.0		$	300.7

The carrying amount and fair value of our financial assets and liabilities at December 31, 2015 and 2014 were (in millions):



	2015				2014
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Assets:
Cash and cash equivalents	$	2,605.2	$	2,605.2	$	2,388.1	$	2,388.1
Short-term investments	14.5		14.5		2.2		2.2
Available-for-sale securities	4.8		4.8		4.9		4.9
Interest rate and foreign currency derivative instruments	32.4		32.4		43.1		43.1
Cost method investments	21.5		21.5		21.8		21.8
Liabilities:
Short-term debt	$	5.2	$	5.2	$	7.2	$	7.2
Interest rate and foreign currency derivative instruments	15.9		15.9		0.4		0.4
Contingent purchase price obligations	322.0		322.0		300.7		300.7
Long-term debt, including current portion	4,565.6		4,655.9		4,542.5		4,754.9

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 long-term debt is based on quoted market prices.