Income Taxes Income taxes (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforward, Federal		$ 40
Tax Credit Carryforward, State		11
Deferred Tax Assets, Valuation Allowance		0
Valuation Allowance, Deferred Tax Asset, Change in Amount	(2)
Unrecognized Tax Benefits		0	0
Unrecognized Tax Benefits, Decreases Resulting from Current Period Tax Positions	$ 2