Income Taxes (Tax Carryforwards and Unrecognized Tax Benefits) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Operating Loss and Tax Credit Carryforwards [Line Items]
Net operating loss carryforwards	$ 557	$ 663
Tax credit carryforwards	2,111	1,819
Liabilities for unrecognized tax benefits		264	279
Cash refund from tax settlement	278
Tax settlement, interest	131
Federal [Member]
Operating Loss and Tax Credit Carryforwards [Line Items]
Tax credit carryforwards	1,813
Expiration dates	2022-2031
State [Member]
Operating Loss and Tax Credit Carryforwards [Line Items]
Tax credit carryforwards	298
Expiration dates	2012-2035
Federal [Member]
Operating Loss and Tax Credit Carryforwards [Line Items]
Net operating loss carryforwards	433
Expiration dates	2026-2031
Years under examination	2009 and 2010
State [Member]
Operating Loss and Tax Credit Carryforwards [Line Items]
Net operating loss carryforwards	110
Expiration dates	2014-2031
Foreign [Member]
Operating Loss and Tax Credit Carryforwards [Line Items]
Net operating loss carryforwards	$ 14
Expiration dates	2021-2031