Financial Statements for Guarantors of the Senior Notes - Statement of Operations and Comprehensive Income - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Income Statements, Captions [Line Items]
Revenues	$ 906.4	$ 973.6	$ 905.5	$ 877.3	$ 1,103.8	$ 1,111.7	$ 1,184.9	$ 1,187.9	$ 3,662.8	$ 4,588.3	$ 6,392.7
Cost of revenues	681.7	722.2	681.9	659.7	841.2	827.3	897.7	889.9	2,745.5	3,456.1	4,656.2
Selling, engineering, and administrative expenses	125.2	114.5	112.8	102.3	101.9	102.3	106.7	96.5	454.8	407.4	476.4
Gains on dispositions on property	44.8	16.1	24.4	1.3	2.9	1.5	11.1	1.9	86.6	17.4	178.8
Cost of revenues and operating costs									3,113.7	3,846.1	4,953.8
Operating Profit (Loss)	144.3	153.0	135.2	116.6	163.6	183.6	191.6	203.4	549.1	742.2	1,438.9
Other (income) expense									177.1	175.4	186.9
Equity in earnings of subsidiaries, net of taxes									0.0	0.0	0.0
Income before income taxes	100.6	107.6	91.3	72.5	115.6	139.5	152.2	159.5	372.0	566.8	1,252.0
Provision (benefit) for income taxes	(439.4)	39.7	37.3	20.8	41.4	49.9	53.4	57.4	(341.6)	202.1	426.0
Net income	540.0	67.9	54.0	51.7	74.2	89.6	98.8	102.1	713.6	364.7	826.0
Net income attributable to noncontrolling interest									11.1	21.1	29.5
Net income attributable to controlling interest	$ 538.5	$ 66.9	$ 51.1	$ 46.0	$ 67.6	$ 84.2	$ 94.6	$ 97.2	702.5	343.6	796.5
Other comprehensive income									11.3	5.0	(0.5)
Comprehensive income									724.9	369.7	825.5
Comprehensive income attributable to noncontrolling interest									13.7	24.2	32.5
Comprehensive income attributable to controlling interest									711.2	345.5	793.0
Reportable legal entities | Parent
Condensed Income Statements, Captions [Line Items]
Revenues									0.0	0.0	0.0
Cost of revenues									3.1	(1.3)	(2.0)
Selling, engineering, and administrative expenses									159.0	125.3	147.0
Gains on dispositions on property									1.0	(0.5)	2.0
Cost of revenues and operating costs									161.1	124.5	143.0
Operating Profit (Loss)									(161.1)	(124.5)	(143.0)
Other (income) expense									(157.2)	(128.8)	(118.7)
Equity in earnings of subsidiaries, net of taxes									671.4	387.5	920.0
Income before income taxes									667.5	391.8	895.7
Provision (benefit) for income taxes									(35.0)	48.2	99.2
Net income									702.5	343.6	796.5
Net income attributable to noncontrolling interest									0.0	0.0	0.0
Net income attributable to controlling interest									702.5	343.6	796.5
Other comprehensive income									8.3	0.6	(6.0)
Comprehensive income									710.8	344.2	790.5
Comprehensive income attributable to noncontrolling interest									0.0	0.0	0.0
Comprehensive income attributable to controlling interest									710.8	344.2	790.5
Reportable legal entities | Combined Guarantor Subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenues									2,275.9	3,267.8	4,956.6
Cost of revenues									1,818.0	2,616.1	3,808.2
Selling, engineering, and administrative expenses									135.5	131.2	162.6
Gains on dispositions on property									71.0	11.1	86.0
Cost of revenues and operating costs									1,882.5	2,736.2	3,884.8
Operating Profit (Loss)									393.4	531.6	1,071.8
Other (income) expense									87.0	73.0	74.0
Equity in earnings of subsidiaries, net of taxes									77.8	91.8	217.3
Income before income taxes									384.2	550.4	1,215.1
Provision (benefit) for income taxes									(295.2)	186.0	370.9
Net income									679.4	364.4	844.2
Net income attributable to noncontrolling interest									0.0	0.0	0.0
Net income attributable to controlling interest									679.4	364.4	844.2
Other comprehensive income									0.1	(0.4)	0.0
Comprehensive income									679.5	364.0	844.2
Comprehensive income attributable to noncontrolling interest									0.0	0.0	0.0
Comprehensive income attributable to controlling interest									679.5	364.0	844.2
Reportable legal entities | Combined Non-Guarantor Subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenues									1,958.6	2,122.6	2,370.8
Cost of revenues									1,520.8	1,671.4	1,808.1
Selling, engineering, and administrative expenses									160.3	150.9	166.8
Gains on dispositions on property									14.6	6.8	90.8
Cost of revenues and operating costs									1,666.5	1,815.5	1,884.1
Operating Profit (Loss)									292.1	307.1	486.7
Other (income) expense									247.3	231.2	231.6
Equity in earnings of subsidiaries, net of taxes									0.0	0.0	0.0
Income before income taxes									44.8	75.9	255.1
Provision (benefit) for income taxes									12.0	25.1	(5.2)
Net income									32.8	50.8	260.3
Net income attributable to noncontrolling interest									0.0	0.0	0.0
Net income attributable to controlling interest									32.8	50.8	260.3
Other comprehensive income									2.9	4.8	5.5
Comprehensive income									35.7	55.6	265.8
Comprehensive income attributable to noncontrolling interest									0.0	0.0	0.0
Comprehensive income attributable to controlling interest									35.7	55.6	265.8
Eliminations
Condensed Income Statements, Captions [Line Items]
Revenues									(571.7)	(802.1)	(934.7)
Cost of revenues									(596.4)	(830.1)	(958.1)
Selling, engineering, and administrative expenses									0.0	0.0	0.0
Gains on dispositions on property									0.0	0.0	0.0
Cost of revenues and operating costs									(596.4)	(830.1)	(958.1)
Operating Profit (Loss)									24.7	28.0	23.4
Other (income) expense									0.0	0.0	0.0
Equity in earnings of subsidiaries, net of taxes									(749.2)	(479.3)	(1,137.3)
Income before income taxes									(724.5)	(451.3)	(1,113.9)
Provision (benefit) for income taxes									(23.4)	(57.2)	(38.9)
Net income									(701.1)	(394.1)	(1,075.0)
Net income attributable to noncontrolling interest									11.1	21.1	29.5
Net income attributable to controlling interest									(712.2)	(415.2)	(1,104.5)
Other comprehensive income									0.0	0.0	0.0
Comprehensive income									(701.1)	(394.1)	(1,075.0)
Comprehensive income attributable to noncontrolling interest									13.7	24.2	32.5
Comprehensive income attributable to controlling interest									$ (714.8)	$ (418.3)	$ (1,107.5)