Related Party Transactions Dow Intercompany Balances (Details) - Dow [Member] - USD ($) $ in Millions	Dec. 31, 2018	Jun. 30, 2018
Related Party Transaction [Line Items]
Accounts Receivable, Related Parties, Current	$ 1	$ 1
Accounts Payable, Related Parties	$ 110	$ 138

Amount of receivables arising from transactions with related parties due within one year or the normal operating cycle, if longer.

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Name:	us-gaap_AccountsReceivableRelatedPartiesCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant