New Accounting Standards New Accounting Standards - Effect of change related to ASU 2016-02 (Details) - Accounting Standards update 2016-02 [Member] $ in Billions	Sep. 30, 2017 USD ($)
Minimum [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use assets	$ 1.5
Lease obligations	1.5
Maximum [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use assets	2.0
Lease obligations	$ 2.0