Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended			9 Months Ended		3 Months Ended		12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Sep. 30, 2014 Forecast item	Sep. 30, 2013 State	Sep. 30, 2014 Federal	Dec. 31, 2010 Federal	Dec. 31, 2012 Federal	Dec. 31, 2011 Federal
Income taxes
Effective tax rate (as a percent)	75.00%	24.00%	36.00%	24.00%
Income tax benefit on uncertain tax positions, expiration of statutes of limitations and settlements on audits							$ 12
Period of cumulative loss position			3 years						3 years
Valuation allowance									372
Increase in valuation allowance										65	89
Tax benefit from release of valuation allowance	517
Net short-term deferred tax assets	265		265		73
Period of cumulative income position						3 years
Number of consecutive quarters of pre-tax earnings						7
Reversal of valuation allowance by the end of 2015						35
Additional tax expense								$ 51