CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($)	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Net (loss) income	$ (33,900,000)	$ (512,400,000)	$ 101,700,000
Other comprehensive income (loss):
Foreign currency translation losses	(8,500,000)	(112,900,000)	(32,500,000)
Net unrealized gain (loss) on derivative instruments
Changes in derivative instruments before reclassification adjustment	11,100,000	11,400,000	13,100,000
Net reclassification adjustment for (gains) losses included in net income	(1,100,000)	(27,500,000)	2,600,000
Changes in derivative instruments after reclassification adjustment	10,000,000	(16,100,000)	15,700,000
Changes in deferred income tax asset/liability	(2,800,000)	5,200,000	(4,200,000)
Deferred tax valuation allowance adjustments	(100,000)	(2,200,000)
Net unrealized gain (loss) on hedging derivative instruments	7,100,000	(13,100,000)	11,500,000
Actuarial adjustments to pension plans
Changes in actuarial adjustments before reclassification adjustment	(41,700,000)	(13,600,000)	(8,700,000)
Net reclassification adjustment for losses included in cost of goods sold	1,400,000	700,000	600,000
Net reclassification adjustment for gains included in selling and general and administrative expenses	1,000,000	700,000	800,000
Changes in actuarial adjustments to pension plans	(39,300,000)	(12,200,000)	(7,300,000)
Changes in deferred income tax asset/liability	10,800,000	3,600,000	2,200,000
Deferred tax valuation allowance adjustments		(3,100,000)	(600,000)
Net actuarial adjustments to pension plans	(28,500,000)	(11,700,000)	(5,700,000)
Unrealized investment gains (losses):
Changes in unrealized investment gains (losses) before reclassification adjustment	784,500,000	(643,800,000)	627,500,000
Net reclassification adjustment for losses (gains) included in net income	8,800,000	28,800,000	(101,000,000)
Changes in unrealized investment gains (losses) after reclassification adjustment	793,300,000	(615,000,000)	526,500,000
Adjustments to intangible assets	(258,300,000)	219,700,000	(156,800,000)
Changes in deferred income tax asset/liability	(185,700,000)	138,700,000	(129,000,000)
Net unrealized gains (losses) on investments	349,300,000.0	(256,600,000)	240,700,000
Non-credit related other-than-temporary impairment:
Net change to derive comprehensive income (loss) for the period	318,000,000	(394,300,000)	214,000,000
Comprehensive income (loss)	284,100,000	(906,700,000)	315,700,000
Less: Comprehensive income (loss) attributable to the noncontrolling interest:
Net income	164,900,000	44,400,000	112,000,000
Other comprehensive income (loss)	56,000,000	(108,000,000)	32,600,000
Total comprehensive income (loss)	220,900,000	(63,600,000)	144,600,000
Comprehensive income (loss) attributable to the controlling interest	63,200,000	(843,100,000)	$ 171,100,000
Non Credit Portion Of Other Than Temporary Impairments Included In Other Comprehensive Income	$ 1,400,000	$ 0