Fair Value

Financial assets and liabilities measured at fair value on a recurring basis at June 30, 2016 and December 31, 2015 were (in millions):



2016	Level 1		Level 2		Level 3		Total
Assets:
Cash and cash equivalents	$	1,305.7					$	1,305.7
Short-term investments	231.0						231.0
Available-for-sale securities	5.1						5.1
Interest rate and foreign currency derivative instruments			$	46.8			46.8
Liabilities:
Foreign currency derivative instruments			$	1.4			$	1.4
Contingent purchase price obligations					$	430.4	430.4



2015
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

The changes in Level 3 contingent purchase price obligations for the six months ended June 30, 2016 and 2015 were (in millions):



	2016			2015
January 1	$	322.0		$	300.7
Acquisitions	150.8			51.6
Revaluation and interest	13.8			3.8
Payments	(62.7		)	(42.3		)
Foreign currency translation	6.5			(7.8		)
June 30	$	430.4		$	306.0

The carrying amount and fair value of our financial instruments at June 30, 2016 and December 31, 2015 were (in millions):



	2016				2015
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Assets:
Cash and cash equivalents	$	1,305.7	$	1,305.7	$	2,605.2	$	2,605.2
Short-term investments	231.0		231.0		14.5		14.5
Available-for-sale securities	5.1		5.1		4.8		4.8
Interest rate and foreign currency derivative instruments	46.8		46.8		32.4		32.4
Cost method investments	14.1		14.1		21.5		21.5
Liabilities:
Short-term debt	$	11.5	$	11.5	$	5.2	$	5.2
Interest rate and foreign currency derivative instruments	1.4		1.4		15.9		15.9
Contingent purchase price obligations	430.4		430.4		322.0		322.0
Long-term debt, including current portion	5,022.4		5,270.0		4,565.6		4,655.9

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.