Condensed Consolidated Statement of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Operating activities:
Net income (loss)	$ (9.0)	$ 404.2
Adjustments to arrive at cash provided by operating activities:
Depreciation	68.5	65.4
Amortization of intangible assets	14.3	15.6
Share-based compensation expense	18.8	20.2
Retirement benefit expense	56.7	86.1
Pension contributions	(23.5)	(28.5)
Net loss on disposition of property	0.0	0.1
Changes in assets and liabilities, excluding effects of acquisitions and foreign currency adjustments:
Receivables	(9.8)	(16.4)
Inventories	(7.9)	(16.6)
Accounts payable	7.2	20.0
Advance payments from customers and deferred revenue	42.8	33.2
Compensation and benefits	(67.7)	51.2
Income taxes	508.6	(7.7)
Other assets and liabilities	(4.9)	(15.0)
Cash provided by operating activities	594.1	611.8
Investing activities:
Capital expenditures	(56.2)	(67.4)
Acquisition of businesses, net of cash acquired	(9.9)	(1.1)
Purchases of investments	(276.6)	(721.6)
Proceeds from maturities of investments	690.3	422.1
Proceeds from sale of investments	155.3	6.1
Proceeds from sale of property	0.4	0.4
Cash provided by (used for) investing activities	503.3	(361.5)
Financing activities:
Net repayment of short-term debt	(41.9)	(75.1)
Repayment of long-term debt	(250.0)	0.0
Cash dividends	(213.5)	(195.5)
Purchases of treasury stock	(661.7)	(185.0)
Proceeds from the exercise of stock options	61.9	136.9
Other financing activities	1.8	0.0
Cash used for financing activities	(1,103.4)	(318.7)
Effect of exchange rate changes on cash	29.0	(17.2)
Increase (decrease) in cash and cash equivalents	23.0	(85.6)
Cash and cash equivalents at beginning of period	1,410.9	1,526.4
Cash and cash equivalents at end of period	$ 1,433.9	$ 1,440.8