Income Taxes (Tax Rate Reconciliation) (Parenthetical) (Details) - USD ($) $ in Millions	12 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017
Income Tax Disclosure [Abstract]
U.S. federal income tax rate	21.00%	21.00%	28.00%	35.00%
Provisional net tax benefit			$ 607

Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
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-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32698-109319

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