Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended			3 Months Ended	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2011	Jun. 30, 2012	Dec. 31, 2011	Mar. 31, 2011 Allegheny	Jun. 30, 2012 Allegheny
Income Tax Contingency [Line Items]
Previously unrecognized tax benefit, impact on effective tax rate from settlement with authorities		$ 3
Decrease in unrecognized tax benefits						21
Income tax benefits on settlement of recognized research and development claim	30
Tax benefits arising from favorable affected tax rate included in Research and development settlement	5	5
Unrecognized tax benefits expected to resolved within the next twelve month			42
Unrecognized benefits (if recognized) affecting effective tax rate	6	6	7
Increase in accrued interest					6
Accrued Interest			12	11
Change in effective tax rate as a result of non-deductible portion of merger transaction and integration costs		$ 28