Income Taxes (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Mar. 31, 2011
Operating Loss Carryforwards
Effective income tax rate	39.40%	33.60%	34.20%
Goodwill impairment		$ 290
Threshhold for payment obligation resulting from tax liability related to spin off	5
Federal Income Tax Expense (Benefit), Continuing Operations [Abstract]
Federal income taxes currently payable	49	72	89
Change in deferred federal income taxes	46	24	(21)
Income Tax Expense (Benefit)	95	96	68
Effective Federal Income Tax Reconciliation [Abstract]
Income tax expense (benefit) on operations at statutory rate	84	(2)	69
Goodwill impairment		101
Manufacturing deduction	(3)	(3)	(1)
Research tax credit		(4)	(3)
Medicare Part D law change			7
Wage credit		(1)
IRS settlement			(8)
Tax Matters Agreement adjustment	8	(3)
Other, Net	6	8	4
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits at beginning of the year	6	14	21	4
Additions based on tax positions related to the current year	7	2
Additions for tax positions of prior years	19		1
Reductions based on tax positions of prior years	(12)
Settlements	(1)		(8)
Spin-off		(10)
Net change in unrecognized tax benefits	13	(8)	(7)
Unrecognized tax benefits at end of the year	19	6	14	4
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	1
Accrued interest on uncertain tax positions	2	3
Recognized Tax Benefits, Resulting From Settlements			(8)
Unrecognized Tax Benefits, Decreases Resulting from Settlements with Taxing Authorities			(10)
Accrued interest on uncertain tax positions, reduction from settlement			(2)
Reasonably possible change in liability for uncertain tax positions	(14)
Reimbursement receivable net of federal benefit, resulting from spin-off				4
Components of Deferred Tax Assets [Abstract]
Retirement benefits	794	618
Workers' compensation	239	219
Contract accounting differences	26	31
Provisions for accrued liabilities	27	63
Stock-based compensation	18	15
Other	37	29
Gross deferred tax assets	1,141	975
Less valuation allowance	21	18
Net deferred tax assets	1,120	957
Components of Deferred Tax Liabilities [Abstract]
Depreciation and amortization	366	347
Purchased intangibles	212	219
Gross deferred tax liabilities	578	566
Valuation allowance	21	18
Net deferred tax assets presented
Net current deferred tax assets	213	232
Net non-current deferred tax assets	329	159
Total net deferred tax assets	542	391
State income taxes
Components of Deferred Tax Liabilities [Abstract]
Operating loss carryforwards	50
State income taxes
Components of Deferred Tax Liabilities [Abstract]
Tax credit carryforward	33
Deferred tax asset, net of federal benefit	21
Research and development credit
Effective Federal Income Tax Reconciliation [Abstract]
Future Research tax credit	$ 2