Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2014

Fair Value Disclosures [Abstract]

Summary of the fair value of financial instruments

The estimated fair values of our other financial instruments at December 31, 2014 and 2013 have been calculated based upon available market information or an appropriate valuation technique, and are as follows:

	December 31, 2014				December 31, 2013
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Level 1:
Senior and senior subordinated notes	$	6,063	$	6,390	$	5,381	$	5,848
Level 2:
4 percent Convertible Senior Notes (1)	32		33		136		149
Level 3:
Capital leases (2)	105		104		120		118

(1) The fair value of the 4 percent Convertible Senior Notes is based on the market value of comparable notes. Consistent with the carrying amount, the fair value excludes the equity component of the notes. To exclude the equity component and calculate the fair value, we used an effective interest rate of 7.3 percent. As discussed below (see note 12), the total cost to settle the notes based on the closing price of our common stock on December 31, 2014 would be $310.

(2) The fair value of capital leases reflects the present value of the leases using a 7.0 percent interest rate.