Fair Value Measurements And Disclosure (Long-Term Debt And Other Financial Instruments) (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Carrying Amount [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Notes and debentures	$ 125,568	$ 124,847
Bank borrowings	4	4
Investment securities	2,550	2,704
Fair Value [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Bank borrowings	4	4
Investment securities	2,550	2,704
Fair Value [Member] | Level 2 [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Notes and debentures	$ 137,112	$ 128,993