Stockholders' Equity (Summary of Changes in Components of Accumulated Other Comprehensive (Loss) Income, Net of Tax ) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019		Mar. 31, 2018
Accumulated Other Comprehensive Income Loss [Line Items]
Balance, beginning of period		$ 10,406	$ 7,953	$ 9,594		$ 6,093
Other comprehensive income, net of tax		2	(95)	5		85
Transferred from Twenty-First Century Fox, Inc. investment		(14)		(157)
Balance, end of period		8,611	$ 8,983	8,611		$ 8,983
Unrealized holding gains on securities
Accumulated Other Comprehensive Income Loss [Line Items]
Balance, beginning of period		0		130
Adoption of ASUs		0		(130)	[1]
Other comprehensive income, net of tax		0		0
Transferred from Twenty-First Century Fox, Inc. investment		0		0
Balance, end of period		0		0
Benefit plan adjustments and other
Accumulated Other Comprehensive Income Loss [Line Items]
Balance, beginning of period		(202)		(49)
Adoption of ASUs		0		(13)	[2]
Other comprehensive income, net of tax		2		5
Transferred from Twenty-First Century Fox, Inc. investment	[3]	(14)		(157)
Balance, end of period		(214)		(214)
Accumulated other comprehensive (loss) income
Accumulated Other Comprehensive Income Loss [Line Items]
Balance, beginning of period		(202)		81
Adoption of ASUs		0		(143)
Other comprehensive income, net of tax		2		5
Transferred from Twenty-First Century Fox, Inc. investment		(14)		(157)
Balance, end of period		$ (214)		$ (214)

[1] Reflects the adoption of ASU 2016-01 (See Note 1 – Description of Business and Basis of Presentation under the heading “Recently Adopted and Recently Issued Accounting Guidance and U.S. Tax Reform” for additional information).

[2] Reflects the adoption of ASU 2018-02 (See Note 1 – Description of Business and Basis of Presentation under the heading “Recently Adopted and Recently Issued Accounting Guidance and U.S. Tax Reform” for additional information).

[3] See Note 10 – Pension and Other Postretirement Benefits.