Summary of Significant Accounting Policies - Schedule of Impact of the Change in Contract Estimates on Operating Results (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Change in Accounting Estimate [Line Items]
Net favorable effect of the changes in contract estimates on net sales	$ 556.5	$ 527.7	$ 512.4	$ 476.1	$ 523.0	$ 481.8	$ 485.0	$ 491.7	$ 2,072.7	$ 1,981.5	$ 1,895.9
Favorable effect of the changes in contract estimates on net income	$ 35.4	$ 31.7	$ 39.2	$ 31.4	$ 25.3	$ 32.9	$ 44.1	$ 38.7	$ 137.7	$ 141.0	$ 137.3
Favorable effect of the changes in contract estimates on basic earnings per share ("EPS") of common stock (in USD per share)	$ 0.46	$ 0.40	$ 0.50	$ 0.40	$ 0.32	$ 0.42	$ 0.56	$ 0.49	$ 1.76	$ 1.79	$ 1.80
Favorable effect of the changes in contract estimates on diluted EPS (in USD per share)	$ 0.43	$ 0.38	$ 0.47	$ 0.37	$ 0.30	$ 0.39	$ 0.54	$ 0.47	$ 1.66	$ 1.69	$ 1.75
Aerospace and Defense | Contracts Accounted for under Percentage-of-Completion
Change in Accounting Estimate [Line Items]
Net favorable effect of the changes in contract estimates on net sales									$ 38.5	$ 38.6	$ 68.2
Favorable effect of the changes in contract estimates on income before income taxes									45.1	38.4	59.1
Favorable effect of the changes in contract estimates on net income									$ 34.5	$ 28.2	$ 43.1
Favorable effect of the changes in contract estimates on basic earnings per share ("EPS") of common stock (in USD per share)									$ 0.44	$ 0.36	$ 0.56
Favorable effect of the changes in contract estimates on diluted EPS (in USD per share)									$ 0.42	$ 0.34	$ 0.55