Financial Information for Guarantor Subsidiaries and Non-Guarantor Subsidiaries - Supplemental Condensed Consolidating Statement of Operations and Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Condensed Financial Statements
Revenue	$ 768.9	$ 720.0	$ 2,260.6	$ 2,131.2
Cost of services, cost of product sales and cost of instant games	290.8	274.3	849.7	806.8
Selling, general and administrative	158.8	152.8	445.4	440.0
Research and development	47.8	53.9	138.3	155.4
Depreciation, amortization and impairments	173.1	191.7	513.2	565.4
Restructuring and other	7.8	13.8	18.1	20.7
Operating (loss) income	90.6	33.5	295.9	142.9
Interest expense	(148.9)	(165.4)	(459.5)	(496.4)
(Loss) gain on debt financing transactions	(8.4)	0.0	(38.1)	25.2
Other (expense) income, net	3.2	13.3	21.4	26.9
Net (loss) income before equity in (loss) income of subsidiaries and income taxes	(63.5)	(118.6)	(180.3)	(301.4)
Equity in (loss) income of subsidiaries	0.0	0.0	0.0	0.0
Income tax benefit (expense)	4.2	19.7	(18.9)	58.5
Net (loss) income	(59.3)	(98.9)	(199.2)	(242.9)
Other comprehensive income	72.8	5.2	140.6	(27.4)
Comprehensive income (loss)	13.5	(93.7)	(58.6)	(270.3)
Reportable Legal Entities | SGI (Issuer)
Condensed Financial Statements
Revenue	129.3	114.2	375.6	355.8
Cost of services, cost of product sales and cost of instant games	88.1	81.8	257.8	250.8
Selling, general and administrative	11.1	14.8	29.1	37.6
Research and development	2.6	1.6	6.4	6.3
Depreciation, amortization and impairments	8.8	8.7	24.3	29.9
Restructuring and other	(0.1)	0.2	0.4	0.4
Operating (loss) income	18.8	7.1	57.6	30.8
Interest expense	(148.5)	(159.5)	(454.2)	(480.0)
(Loss) gain on debt financing transactions	(8.4)		(37.0)	25.2
Other (expense) income, net	59.4	54.7	161.8	157.5
Net (loss) income before equity in (loss) income of subsidiaries and income taxes	(78.7)	(97.7)	(271.8)	(266.5)
Equity in (loss) income of subsidiaries	22.5	7.5	54.4	37.8
Income tax benefit (expense)	29.4	99.2	101.7	99.2
Net (loss) income	(26.8)	9.0	(115.7)	(129.5)
Other comprehensive income	4.6	2.1	8.9	5.0
Comprehensive income (loss)	(22.2)	11.1	(106.8)	(124.5)
Reportable Legal Entities | SGC (Parent and Issuer)
Condensed Financial Statements
Revenue	0.0	0.0	0.0	0.0
Cost of services, cost of product sales and cost of instant games	0.0	0.0	0.0	0.0
Selling, general and administrative	30.8	30.9	89.7	91.9
Research and development	0.5	2.1	1.7	4.8
Depreciation, amortization and impairments	22.3	13.8	59.5	39.5
Restructuring and other	7.0	14.3	12.3	14.3
Operating (loss) income	(60.6)	(61.1)	(163.2)	(150.5)
Interest expense	(0.1)	(5.3)	(4.4)	(15.8)
(Loss) gain on debt financing transactions	0.0		(1.1)	0.0
Other (expense) income, net	(21.2)	(13.9)	(60.1)	(64.2)
Net (loss) income before equity in (loss) income of subsidiaries and income taxes	(81.9)	(80.3)	(228.8)	(230.5)
Equity in (loss) income of subsidiaries	26.1	18.1	49.6	(22.7)
Income tax benefit (expense)	(3.5)	(36.7)	(20.0)	10.3
Net (loss) income	(59.3)	(98.9)	(199.2)	(242.9)
Other comprehensive income	72.8	5.2	140.6	(27.4)
Comprehensive income (loss)	13.5	(93.7)	(58.6)	(270.3)
Reportable Legal Entities | Guarantor Subsidiaries
Condensed Financial Statements
Revenue	400.0	330.8	1,220.3	1,047.0
Cost of services, cost of product sales and cost of instant games	120.7	86.1	373.4	275.2
Selling, general and administrative	60.9	43.1	178.6	132.8
Research and development	26.0	38.3	77.1	109.1
Depreciation, amortization and impairments	111.6	140.6	346.3	407.3
Restructuring and other	0.1	(0.7)	3.2	3.3
Operating (loss) income	80.7	23.4	241.7	119.3
Interest expense	0.0	0.0	0.0	0.0
(Loss) gain on debt financing transactions	0.0		0.0	0.0
Other (expense) income, net	(14.5)	(26.7)	(71.0)	(73.9)
Net (loss) income before equity in (loss) income of subsidiaries and income taxes	66.2	(3.3)	170.7	45.4
Equity in (loss) income of subsidiaries	15.5	37.9	37.0	85.3
Income tax benefit (expense)	(31.0)	(16.9)	(79.0)	(16.8)
Net (loss) income	50.7	17.7	128.7	113.9
Other comprehensive income	53.2	(48.0)	119.4	(54.2)
Comprehensive income (loss)	103.9	(30.3)	248.1	59.7
Reportable Legal Entities | Non-Guarantor Subsidiaries
Condensed Financial Statements
Revenue	311.6	358.4	861.0	942.2
Cost of services, cost of product sales and cost of instant games	152.7	189.8	410.1	494.6
Selling, general and administrative	70.1	64.0	184.6	177.7
Research and development	18.7	11.9	53.1	35.2
Depreciation, amortization and impairments	33.5	28.6	90.9	88.7
Restructuring and other	0.8	0.0	2.2	2.7
Operating (loss) income	35.8	64.1	120.1	143.3
Interest expense	(0.3)	(0.6)	(0.9)	(0.6)
(Loss) gain on debt financing transactions	0.0		0.0	0.0
Other (expense) income, net	(20.5)	(0.8)	(9.3)	7.5
Net (loss) income before equity in (loss) income of subsidiaries and income taxes	15.0	62.7	109.9	150.2
Equity in (loss) income of subsidiaries	0.0	0.0	0.0	0.0
Income tax benefit (expense)	9.3	(25.9)	(21.6)	(34.2)
Net (loss) income	24.3	36.8	88.3	116.0
Other comprehensive income	67.0	19.0	126.7	(11.8)
Comprehensive income (loss)	91.3	55.8	215.0	104.2
Eliminating Entries
Condensed Financial Statements
Revenue	(72.0)	(83.4)	(196.3)	(213.8)
Cost of services, cost of product sales and cost of instant games	(70.7)	(83.4)	(191.6)	(213.8)
Selling, general and administrative	(14.1)	0.0	(36.6)	0.0
Research and development	0.0	0.0	0.0	0.0
Depreciation, amortization and impairments	(3.1)	0.0	(7.8)	0.0
Restructuring and other	0.0	0.0	0.0	0.0
Operating (loss) income	15.9	0.0	39.7	0.0
Interest expense	0.0	0.0	0.0	0.0
(Loss) gain on debt financing transactions	0.0		0.0	0.0
Other (expense) income, net	0.0	0.0	0.0	0.0
Net (loss) income before equity in (loss) income of subsidiaries and income taxes	15.9	0.0	39.7	0.0
Equity in (loss) income of subsidiaries	(64.1)	(63.5)	(141.0)	(100.4)
Income tax benefit (expense)	0.0	0.0	0.0	0.0
Net (loss) income	(48.2)	(63.5)	(101.3)	(100.4)
Other comprehensive income	(124.8)	26.9	(255.0)	61.0
Comprehensive income (loss)	$ (173.0)	$ (36.6)	$ (356.3)	$ (39.4)