Basis Of Presentation (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016	Jan. 01, 2016
Basis of Presentation [Line Items]
Change in diluted earnings per share due to net favorable/(unfavorable) cumulative catch-up adjustments	$ 0.27	$ (0.39)	$ 0.31	$ (0.70)
Increase/(Decrease) in Earnings from operations due to change in accounting estimate	$ 231,000,000	$ (503,000,000)	$ 263,000,000	$ (587,000,000)
Pro Forma [Member] | Retained Earnings [Member]
Basis of Presentation [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets						$ 1,000
Pro Forma [Member] | Sales Revenue, Net [Member]
Basis of Presentation [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets						10,000
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification					$ 1,000
Pro Forma [Member] | Operating Income (Loss) [Member]
Basis of Presentation [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets						$ 1,000
Assets [Member] | Pro Forma [Member]
Basis of Presentation [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification					20,000
Defense Contracts [Member] | Pro Forma [Member] | Sales Revenue, Net [Member]
Basis of Presentation [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification					2,000
Operating Segments [Member] | Pro Forma [Member] | Operating Income (Loss) [Member]
Basis of Presentation [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification					$ 400