|
Earnings Per Share (Details) (USD $)
In Millions, except Share data in Thousands, unless otherwise specified
|
3 Months Ended |
|
Mar. 31, 2015
|
Mar. 31, 2014
|
| Numerator: |
|
|
| Net income available to common stockholders |
$ 115 |
$ 60 |
| Denominator: |
|
|
| Denominator for basic earnings per share—weighted-average common shares (in shares) |
97,007 |
95,225 |
| Effect of dilutive securities: |
|
|
| Convertible subordinated notes—4 percent (in shares) |
1,185 |
10,224 |
| Denominator for diluted earnings per share—adjusted weighted-average common shares (in shares) |
99,065 |
106,424 |
| Basic earnings per share (in dollars per share) |
$ 1.19 |
$ 0.63 |
| Diluted earnings per share (in dollars per share) |
$ 1.16 |
$ 0.56 |
| Convertible senior notes | Convertible subordinated notes—4 percent |
|
|
| Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items] |
|
|
| Stated interest rate |
4.00% |
4.00% |
| Employee stock options and warrants |
|
|
| Effect of dilutive securities: |
|
|
| Effect of dilutive securities, share-based payment arrangements (in shares) |
336 |
435 |
| Restricted stock units |
|
|
| Effect of dilutive securities: |
|
|
| Effect of dilutive securities, share-based payment arrangements (in shares) |
537 |
540 |