Fair Value Measurements (Aggregate Fair Value of Derivative Financial Instruments And Debt) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Quoted Prices In Active Markets For Identical Assets/Liabilities (Level 1) [Member]
Assets:
Foreign exchange contracts	$ 0	$ 0
Pension plan assets	4,420	4,513
Total assets in fair value hierarchy	4,420	4,513
Liabilities:
Debt	29,756	28,822
Foreign exchange contracts	0	0
Total liabilities	29,756	28,822
Significant Other Observable Inputs (Level 2) [Member]
Assets:
Foreign exchange contracts	813	574
Pension plan assets	1,740	1,593
Total assets in fair value hierarchy	2,553	2,167
Liabilities:
Debt	436	465
Foreign exchange contracts	163	172
Total liabilities	599	637
Fair Value, Inputs, Level 3 [Member]
Assets:
Foreign exchange contracts	0	0
Pension plan assets	0	0
Total assets in fair value hierarchy	0	0
Liabilities:
Debt	0	0
Foreign exchange contracts	0	0
Total liabilities	0	0
Estimate of Fair Value, Fair Value Disclosure [Member]
Assets:
Foreign exchange contracts	813	574
Pension plan assets	6,160	6,106
Total assets in fair value hierarchy	6,973	6,680
Alternative Investments, Fair Value Disclosure	297	298
Total assets in fair value hierarchy	7,270	6,978
Liabilities:
Debt	30,192	29,287
Foreign exchange contracts	163	172
Total liabilities	$ 30,355	$ 29,459