Short-Term Borrowings (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Short-term Debt
Short-term borrowings, Balance	$ 7,094	$ 6,958
Commercial paper, net
Short-term Debt
Short-term borrowings, Balance	$ 5,985	$ 5,811
Short-term borrowings, Avg. Rate	0.90%	0.50%
Bank borrowings
Short-term Debt
Short-term borrowings, Balance	$ 553	$ 440
Short-term borrowings, Avg. Rate	7.50%	9.30%
Variable denomination floating rate demand notes
Short-term Debt
Short-term borrowings, Balance	$ 556	$ 707
Short-term borrowings, Avg. Rate	0.90%	0.80%