Debt (Tables)

12 Months Ended

Dec. 31, 2015

Debt Disclosure [Abstract]

The Carrying Value Of Long-Term Debt

The carrying value of long-term debt at December 31 consists of the following:

	2015		2014
Senior unsecured notes:
1.250%, due 2015	$	—	$	624.3
2.375%, due 2017	399.9		398.9
5.875%, due 2017	527.6		526.7
1.875%, due 2018	621.9		616.4
2.300%, due 2018	645.9		644.3
2.250%, due 2019	843.9		842.1
7.000%, due 2019	438.9		438.5
4.350%, due 2020	702.9		695.3
3.700%, due 2021	696.2		695.6
3.125%, due 2022	842.7		841.6
3.300%, due 2023	992.2		991.2
3.500%, due 2024	790.9		789.8
5.950%, due 2034	444.5		444.4
5.850%, due 2036	768.0		767.7
6.375%, due 2037	639.6		639.3
5.800%, due 2040	193.8		206.4
4.625%, due 2042	885.8		885.4
4.650%, due 2043	985.5		985.0
4.650%, due 2044	790.5		790.1
5.100%, due 2044	593.3		593.1
4.850%, due 2054	246.6		246.5
Remarketable subordinated notes:
1.900%, due 2028	1,236.1		—
Surplus notes:
9.000%, due 2027	24.9		24.9
Senior convertible debentures:
2.750%, due 2042	330.7		956.4
Variable rate debt:
Commercial paper program	682.2		—
Total long-term debt	15,324.5		14,643.9
Current portion of long-term debt	—		(624.3		)
Long-term debt, less current portion	$	15,324.5	$	14,019.6

Convertible Debenture Terms

The following table summarizes at December 31, 2015 the related balances, conversion rate and conversion price of the Debentures:

Outstanding principal amount	$	513.4
Unamortized debt discount	$	176.8
Net debt carrying amount	$	330.7
Equity component carrying amount	$	186.1
Conversion rate (shares of common stock per $1,000 of principal amount)	13.4886
Effective conversion price (per $1,000 of principal amount)	$	74.1360