Stock Based Compensation Nonvested Stock Option Activity (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Summary of nonvested stock activity
Instrinsic value of stock options exercised	$ 1	$ 2
Granted, Shares	1,389,452	1,020,979
Nonvested Stock Options [Member]
Summary of nonvested stock activity
Stock Options Shares Outstanding, Beginning balance	3,110,523	4,036,595
Granted, Shares	1,389,452	1,020,979
Vested, Shares	(1,451,304)	(1,680,981)
Forfeited, Shares	(51,819)	(266,070)
Stock Options Shares Outstanding, Ending balance	2,996,852	3,110,523
Nonvested Weighted Average Grant Date Fair Value, Beginning balance	$ 4.69	$ 5.11
Granted Weighted Average Grant Date Fair Value	$ 3.00	$ 3.80
Vested Weighted Average Grant Date Fair Value	$ 4.96	$ 5.10
Forfeited Weighted Average Grant Date Fair Value	$ 4.85	$ 5.05
Nonvested Weighted Average Grant Date Fair Value, Ending balance	$ 3.77	$ 4.69