Investments and Related Matters Other Segments (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Schedule of Investments [Line Items]
Investments	$ 9,987	$ 15,351
Other investments
Schedule of Investments [Line Items]
Investments	9,685	15,028
Other Segments [Member]
Schedule of Investments [Line Items]
Investments	670	798
Other Segments [Member] | Equity method investments
Schedule of Investments [Line Items]
Investments	302	323
Other Segments [Member] | Other investments
Schedule of Investments [Line Items]
Investments	$ 368	$ 475