Equity-Based Compensation (Summary of Equity-Based Compensation) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Equity-based compensation	[1]	$ 38	$ 41	$ 71	$ 69
Intrinsic value of all settled equity-based awards		$ 130	$ 0	$ 240	$ 31

[1] Prior to the Distribution, equity-based compensation included allocated expense for both executive directors and corporate executives of 21CF, allocated using a proportional allocation driver, which management has deemed to be reasonable.