Accounting Policies (Details) $ in Millions	Sep. 30, 2017 USD ($)
Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets	$ 9
Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating Lease Right Of Use Asset Expected	100
Operating Lease Liability Expected	$ 100