Income Taxes Income Taxes Reconciliation of the beginning and ending amount of unrecognized tax benefits (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Tax Credit Carryforward [Line Items]
Gross unrecognized tax benefits, beginning of period	$ 81	$ 129	$ 220
Current year tax positions	8	6	11
Prior year tax positions	5	18	10
Prior year tax positions	0	(48)	(34)
Settlements	0	(10)	(25)
Statute of limitations lapses	(5)	(14)	(53)
Gross unrecognized tax benefits, end of period	$ 89	$ 81	$ 129