Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2016

Fair Value Disclosures [Abstract]

Summary of assets and liabilities recorded at fair value

(In millions)	As of December 31, 2016		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	$	2,039.6	$	—	$	2,039.6	$	—
Marketable debt securities:
Corporate debt securities	2,663.8		—		2,663.8		—
Government securities	2,172.5		—		2,172.5		—
Mortgage and other asset backed securities	561.7		—		561.7		—
Marketable equity securities	24.9		24.9		—		—
Derivative contracts	61.0		—		61.0		—
Plan assets for deferred compensation	34.5		—		34.5		—
Total	$	7,558.0	$	24.9	$	7,533.1	$	—
Liabilities:
Derivative contracts	$	13.6	$	—	$	13.6	$	—
Contingent consideration obligations	467.6		—		—		467.6
Total	$	481.2	$	—	$	13.6	$	467.6

(In millions)	As of December 31, 2015		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	$	909.5	$	—	$	909.5	$	—
Marketable debt securities:
Corporate debt securities	1,510.9		—		1,510.9		—
Government securities	2,875.9		—		2,875.9		—
Mortgage and other asset backed securities	494.1		—		494.1		—
Marketable equity securities	37.5		37.5		—		—
Derivative contracts	27.2		—		27.2		—
Plan assets for deferred compensation	40.1		—		40.1		—
Total	$	5,895.2	$	37.5	$	5,857.7	$	—
Liabilities:
Derivative contracts	$	14.7	$	—	$	14.7	$	—
Contingent consideration obligations	506.0		—		—		506.0
Total	$	520.7	$	—	$	14.7	$	506.0

Summary of fair and carrying value of debt instruments

	As of December 31,
(In millions)	2016		2015
Notes payable to Fumedica	$	6.1	$	9.4
6.875% Senior Notes due March 1, 2018	583.7		602.6
2.900% Senior Notes due September 15, 2020	1,521.5		1,497.5
3.625% Senior Notes due September 15, 2022	1,026.6		1,014.2
4.050% Senior Notes due September 15, 2025	1,796.0		1,764.6
5.200% Senior Notes due September 15, 2045	1,874.5		1,757.6
Total	$	6,808.4	$	6,645.9

Fair value of contingent consideration obligations

	As of December 31,
(In millions)	2016			2015
Fair value, beginning of year	$	506.0		$	215.5
Additions	—			274.5
Changes in fair value	14.8			30.5
Payments and other	(53.2		)	(14.5		)
Fair value, end of year	$	467.6		$	506.0