Debt (Tables)

12 Months Ended

Dec. 31, 2014

Debt Disclosure [Abstract]

Key Components of Convertible Debt

Our long-term debt as of December 31, 2014 was as follows (dollars in millions):

Senior Notes	Issued at Discount to Par		Carrying Value
$2.5 billion 1.875% Notes due 2018	99.943	%	$	2,499
$2.0 billion 2.650% Notes due 2020	99.760	%	1,996
$1.0 billion 3.375% Notes due 2023	99.925	%	1,000
			$	5,495

The following table represents the key components of our interest expense on convertible debt (table in millions):

	For the year ended
	2013		2012
Contractual interest expense on the coupon	$	27	$	30
Amortization of the discount component recognized as interest expense	58		61
Total interest expense on the convertible debt	$	85	$	91