Earnings Per Share, Share Repurchases and Dividends on Common Stock (Unaudited) (Details 1) - September 2015 Share Repurchase Program Original Authorization - USD ($) $ / shares in Units, shares in Millions, $ in Millions	6 Months Ended		27 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Sep. 16, 2015
Share Repurchase [Line Items]
Amount Authorized				$ 4,000
Shares Retired			7.6
Average Cost Per Share			$ 224.82
Shares Repurchased	0.2	1.5
Share Repurchases - Notes to Table
Shares repurchased amount			$ 1,700
Amount remaining under authorization for share repurchases	$ 2,300		$ 2,300