Retirement Benefits (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Sep. 30, 2013
Defined Benefit Plan Disclosure [Line Items]
Company contributions	$ 76.4	$ 31.4	$ 78.2
Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Total expected contributions for current fiscal year	130
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Total expected contributions for current fiscal year	$ 150