Repurchase of Common Stock Authorized Common Stock Repurchases (Details) - USD ($) $ in Billions	Jul. 29, 2017	Feb. 27, 2017	Jun. 30, 2011
February 2017 share repurchase program [Member]
Authorized Share Repurchases [Line Items]
Stock Repurchase Program, Authorized Amount		$ 5.0
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 4.3
June 2011 share repurchase program [Member}
Authorized Share Repurchases [Line Items]
Stock Repurchase Program, Authorized Amount			$ 5.0