Fair Value

Financial assets and liabilities measured at fair value on a recurring basis at December 31, 2014 and 2013 were (in millions):



2014	Level 1		Level 2		Level 3		Total
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



2013
Assets:
Cash and cash equivalents	$	2,710.5					$	2,710.5
Short-term investments	18.2						18.2
Available-for-sale securities	4.9						4.9
Foreign currency derivative instruments			$	2.2			2.2
Liabilities:
Foreign currency derivative instruments			$	0.1			$	0.1
Contingent interest derivative			2.1				2.1
Contingent purchase price obligations					$	220.2	220.2

The changes in Level 3 contingent purchase price obligations for the years ended December 31, 2014 and 2013 were (in millions):



	2014			2013
January 1	$	220.2		$	266.2
Acquisitions	167.1			35.8
Revaluation and interest	11.0			(10.9		)
Payments	(83.2		)	(70.5		)
Foreign currency translation	(14.4		)	(0.4		)
December 31	$	300.7		$	220.2

The carrying amount and fair value of our financial instruments at December 31, 2014 and 2013 were (in millions):



	2014				2013
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Assets:
Cash and cash equivalents	$	2,388.1	$	2,388.1	$	2,710.5	$	2,710.5
Short-term investments	2.2		2.2		18.2		18.2
Available-for-sale securities	4.9		4.9		4.9		4.9
Interest rate and foreign currency derivative instruments	43.1		43.1		2.2		2.2
Cost method investments	21.8		21.8		22.2		22.2
Liabilities:
Short-term borrowings	$	7.2	$	7.2	$	5.9	$	5.9
Foreign currency derivative instruments	0.4		0.4		0.1		0.1
Contingent interest derivative	—		—		2.1		2.1
Contingent purchase price obligations	300.7		300.7		220.2		220.2
Debt	4,563.0		4,754.9		4,033.8		4,302.7

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.