Stock-Based Compensation (Restricted Stock Units) (Details)
$ / shares in Units, $ in Millions |
12 Months Ended |
|
Dec. 31, 2015
USD ($)
installment
$ / shares
shares
|
Dec. 31, 2014
USD ($)
$ / shares
shares
|
Dec. 31, 2013
USD ($)
$ / shares
shares
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
| Number of common shares available for issuance |
243,331
|
233,017
|
|
| Restricted stock units |
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
| Annual vesting percentage |
33.33%
|
|
|
| Share-based compensation expense | $ |
$ 3
|
$ 3
|
$ 1
|
| Market value of restricted stock units | $ |
$ 9
|
$ 4
|
|
| Shares |
|
|
|
| Non-vested balance at beginning of period (shares) |
233,691
|
287,926
|
425,211
|
| Granted (shares) |
1,325,134
|
279,312
|
113,760
|
| Vested (shares) |
(152,220)
|
(276,548)
|
(190,949)
|
| Canceled and forfeited (shares) |
(106,620)
|
(56,999)
|
(60,096)
|
| Non-vested balance at end of period (shares) |
1,299,985
|
233,691
|
287,926
|
| Weighted — Average Grant-Date Fair Value per Share |
|
|
|
| Non-vested balance at beginning of period (in usd per share) | $ / shares |
$ 17.21
|
$ 12.01
|
$ 12.70
|
| Granted (in usd per share) | $ / shares |
16.11
|
19.27
|
15.06
|
| Vested (in usd per share) | $ / shares |
15.25
|
14.47
|
17.08
|
| Canceled and forfeited (in usd per share) | $ / shares |
18.46
|
14.37
|
11.14
|
| Non-vested balance at end of period (in usd per share) | $ / shares |
$ 16.36
|
$ 17.21
|
$ 12.01
|
| 2006 Plan |
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
| Share-based compensation expense | $ |
$ 3
|
$ 4
|
$ 5
|
| 2006 Plan | Restricted stock units |
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
| Number of common shares available for issuance |
437,402
|
737,861
|
|
| Executive Long-Term Incentive Plan | Restricted stock units |
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
| Performance period for stock to achieve before grant of ExLTIP shares (in years) |
10 years
|
|
|
| Number of Annual Installments | installment |
5
|
|
|
| Weighted — Average Grant-Date Fair Value per Share |
|
|
|
| ExLTIP shares pending approval (in shares) |
907,741
|
|
|