Equity (Details) (USD $)	1 Months Ended	3 Months Ended
	Oct. 24, 2013	Mar. 31, 2014	Mar. 31, 2013
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Exercise Price of Warrants or Rights		9.478
Repurchase of warrants			$ (3,000,000)
Warrants outstanding		22,600,000
Stock repurchase authorized amount		2,000,000,000
Common Stock [Member]
Class of Warrant or Right [Line Items]
Treasury stock acquired	8,700,000	8,821,000	1,765,000
Treasury Stock [Member]
Class of Warrant or Right [Line Items]
Common stock repurchased, value	300,000,000	300,000,000	45,000,000
Additional Paid-in Capital [Member]
Class of Warrant or Right [Line Items]
Repurchase of warrants		$ 0	$ 3,000,000