Pension and Other Postretirement Benefits (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Jan. 31, 2019
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension benefit assets	$ 630		$ 630
Projected benefit obligations	765		765
Pension benefit, accumulated other comprehensive loss	188		188
Pension benefit, accumulated other comprehensive loss, net of tax	143		143
Net periodic benefit cost	$ 14	$ 63	$ 27	$ 74
Postretirement Benefits | Subsequent Event
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligations					$ 98
Pension benefit, accumulated other comprehensive loss					18
Pension benefit, accumulated other comprehensive loss, net of tax					$ 14