Stockholders' Equity (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	Jul. 17, 2017	Jun. 30, 2017
Subsequent Event [Line Items]
Stock Repurchase Program, Remaining Authorized Repurchase Amount		$ 228
Subsequent Event [Member]
Subsequent Event [Line Items]
Stock Repurchase Program, Authorized Amount	$ 1,500
Dividends Payable, Amount Per Share	$ 0.46
Dividends Payable	$ 63