Income Taxes (Reconciliation From Statutory Federal Income Tax Rate To Effective Income Tax Rate) (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Statutory federal income tax rate	21.00%	21.00%	35.00%
State tax on commercial operations, net of federal benefits	0.70%	1.10%	0.60%
Impact of international operations	0.20%	0.60%	(4.50%)
Domestic production deduction	0.00%	0.00%	(1.50%)
Foreign derived intangible income	(1.40%)	(1.20%)	0.00%
Equity-based compensation	(1.10%)	(1.10%)	(2.60%)
Domestic tax credits	(2.00%)	(1.10%)	(0.80%)
Contract close-outs	0.00%	(0.50%)	0.00%
Adoption impact of enacted change in U.S. tax law	0.00%	0.00%	2.90%
Other, net	(0.30%)	(1.00%)	(0.50%)
Effective income tax rate	17.10%	17.80%	28.60%