Income Taxes Net Unrecognized Tax Benefits (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	$ 223	$ 265
Additions based on tax positions related to the current year	18	81
Additions for tax positions of prior years	80	54
Reductions for tax positions of prior years	(106)	(90)
Statute of limitations	4	(68)
Settlements	(10)	(8)
Interest and penalties	2	(11)
Ending balance	211	223
Unrecognized tax benefits that would impact effective tax rate	179	113
Unrecognized tax benefits that would not impact the effective tax rate	$ 32	$ 110