Discontinued Operations Discontinued Operations (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Operating Income (Loss)	$ 223	$ 294	$ 633	$ 606
Income Tax Expense (Benefit)	44	70	149	143
Segment, Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Revenue		12		22
Disposal Group, Including Discontinued Operation, Operating Expense		5		10
Depreciation and Amortization, Discontinued Operations		6		11
Taxes Other than Income Related to Discontinued Operations		1		1
Operating Income (Loss)		0		0
Other Nonoperating Income (Expense)		2		3
Income Tax Expense (Benefit)		(1)		(2)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent		$ (1)		$ (1)