Financial Statement Presentation New Accounting Pronouncement Adopted (Details) $ in Millions	Dec. 31, 2016 USD ($)
Retained Earnings [Member] | Accounting Standard Update 2016-09 [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	$ 31
Deferred Income Tax Charge [Member] | Accounting Standard Update 2016-09 [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	31
Other Expense [Member] | Accounting Standard Update 2017-07 [Member] [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	$ 144