Summary of Significant Accounting Policies (Narrative) (Details) shares in Millions, $ in Millions			3 Months Ended	12 Months Ended
		Mar. 19, 2019 shares	Dec. 31, 2017 USD ($)	Jun. 30, 2019 USD ($) Customer	Jun. 30, 2018 USD ($) Customer	Jun. 30, 2017 USD ($)	Jul. 01, 2018 USD ($)
Marketing and Advertising Expense [Abstract]
Advertising expense				$ 388	$ 392	$ 366
Shares distributed to stockholders of the Parent | shares		621
Concentrations of Credit Risk [Abstract]
Cumulative effect of adoption of new accounting standards	[1]				$ 0
U.S. statutory federal rate				21.00%	28.00%	35.00%
Tax Cuts and Jobs Act, maximum measurement period to finalize recording of related tax impacts from enactment date				1 year
Provisional income tax benefit to reflect the impact of the Tax Act			$ 624		$ 607
Unrealized holding gains on securities | ASU 2016-01
Concentrations of Credit Risk [Abstract]
Cumulative effect of adoption of new accounting standards							$ 130
Benefit plan adjustments and other | ASU 2018-02
Concentrations of Credit Risk [Abstract]
Cumulative effect of adoption of new accounting standards							$ 13
Receivables | Credit Concentration Risk
Concentrations of Credit Risk [Abstract]
Concentration Risk, Percentage				10.00%	21.00%
Number of major customers | Customer				0	2
Leasehold Improvements
Property, Plant and Equipment [Abstract]
Property, plant and equipment, estimated useful lives				straight-line method over the shorter of their useful lives or the life of the lease
Minimum
Property, Plant and Equipment [Abstract]
Property, plant and equipment, useful life				3 years
Maximum
Property, Plant and Equipment [Abstract]
Property, plant and equipment, useful life				40 years

[1] Reflects the adoption of ASU 2016-01 and ASU 2018-02 as defined in Note 2—Summary of Significant Accounting Policies under the heading “Adopted.”