Employee Benefit Plans (Components Of Stock-Based Compensation Expense) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Jun. 30, 2018
Defined Benefit Plan Disclosure [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period			4 years
Risk-free interest rate	2.70%	1.80%
Dividend yield	1.90%	2.10%
Weighted average volatility factor	20.90%	21.70%
Weighted average expected life (in years)	5 years 5 months	5 years 5 months
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	4,523		3,983
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 98		$ 87
Options granted	836
Options granted	$ 147
Options exercised	284
Options exercised	$ 78
Options canceled/forfeited	12
Options canceled/forfeited	$ 106
Total pre-tax stock-based compensation expense	$ 38.4	$ 39.0
Weighted average fair value (in dollars)	$ 26.60	$ 17.50
Operating expenses
Defined Benefit Plan Disclosure [Line Items]
Total pre-tax stock-based compensation expense	$ 5.4	$ 5.2
Selling, general and administrative expenses
Defined Benefit Plan Disclosure [Line Items]
Total pre-tax stock-based compensation expense	28.0	28.6
System development and programming costs
Defined Benefit Plan Disclosure [Line Items]
Total pre-tax stock-based compensation expense	$ 5.0	$ 5.2
Time Based Restriced Stock granted during or after Fiscal 2019 [Domain]
Defined Benefit Plan Disclosure [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Time Based Restricted Stock granted during Fiscal 2013 [Domain]
Defined Benefit Plan Disclosure [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period			2 years
Nonvested Stock Options [Member]
Defined Benefit Plan Disclosure [Line Items]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$ 29.3
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	2 years 6 months
Restricted Stock Units (RSUs) [Member]
Defined Benefit Plan Disclosure [Line Items]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$ 83.6
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	1 year 9 months
Nonvested Restricted Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$ 126.7
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	2 years 1 month