Debt (Tables)

12 Months Ended

Dec. 31, 2016

Debt Disclosure [Abstract]

The Carrying Value Of Long-Term Debt

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

	2016			2015
Senior unsecured notes:
2.375%, due 2017	$	400.1		$	399.9
5.875%, due 2017	528.3			527.6
1.875%, due 2018	624.3			621.9
2.300%, due 2018	647.5			645.9
2.250%, due 2019	845.6			843.9
7.000%, due 2019	439.4			438.9
4.350%, due 2020	700.0			702.9
3.700%, due 2021	696.9			696.2
3.125%, due 2022	843.8			842.7
3.300%, due 2023	993.3			992.2
3.500%, due 2024	791.9			790.9
5.950%, due 2034	444.7			444.5
5.850%, due 2036	768.3			768.0
6.375%, due 2037	639.9			639.6
5.800%, due 2040	193.9			193.8
4.625%, due 2042	886.3			885.8
4.650%, due 2043	985.9			985.5
4.650%, due 2044	790.8			790.5
5.100%, due 2044	593.6			593.3
4.850%, due 2054	246.8			246.6
Remarketable subordinated notes:
1.900%, due 2028	1,237.6			1,236.1
Surplus notes:
9.000%, due 2027	24.9			24.9
Senior convertible debentures:
2.750%, due 2042	334.1			330.7
Variable rate debt:
Commercial paper program	629.0			682.2
Total long-term debt	15,286.9			15,324.5
Current portion of long-term debt	(928.4		)	—
Long-term debt, less current portion	$	14,358.5		$	15,324.5

Convertible Debenture Terms

The following table summarizes at December 31, 2016 the related balances, conversion rate and conversion price of the Debentures:

Outstanding principal amount	$	513.4
Unamortized debt discount	$	173.6
Net debt carrying amount	$	334.1
Equity component carrying amount	$	186.1
Conversion rate (shares of common stock per $1,000 of principal amount)	13.6368
Effective conversion price (per $1,000 of principal amount)	$	73.3306