Pension and Other Postretirement Benefits (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Jan. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost	$ 13	$ 15	$ 40	$ 89
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension benefit assets						$ 630
Projected benefit obligations						765
Pension benefit, accumulated other comprehensive loss						188
Pension benefit, accumulated other comprehensive loss, net of tax						$ 143
Postretirement Benefits
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