Consolidated Statement of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Other comprehensive income (loss):
Tax expense (benefit) from pension and other postretirement benefit plan adjustments	$ 87.2	$ 159.3	$ (73.7)
Tax expense (benefit) from net change in unrealized gains and losses on cash flow hedges	$ 6.6	$ (2.8)	$ (6.7)

Amount, after reclassification adjustment, of tax (expense) benefit for (increase) decrease in accumulated other comprehensive income of defined benefit plan.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=114867106&loc=d3e640-108580

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (i-k)
-URI http://asc.fasb.org/extlink&oid=114867106&loc=SL7669646-108580

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 19
-URI http://asc.fasb.org/extlink&oid=108774443&loc=SL4569616-111683

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