Financial Statement Presentation New Accounting Pronouncement Adopted (Details) - Accounting Standard Update 2016-09 [Member] $ in Millions	Dec. 31, 2016 USD ($)
Retained Earnings [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	$ 31
Deferred Income Tax Charge [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	$ 31