Fair Value Measurements - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2015	Dec. 31, 2013	Mar. 31, 2014	Mar. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying amount of liabilities	$ 9,700			$ 8,100
Brazil Distribution Business
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pre tax impairment charges	241
Impairment charges, after tax	235
International Technology
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pre tax impairment charges		$ 80
Impairment charges, after tax		$ 80
Level 2 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of liabilities	10,400			$ 8,600
Level 3 | Fair Value, Measurements, Nonrecurring | Brazil Distribution Business
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pre tax impairment charges	241
Impairment charges, after tax	$ 235
Level 3 | Fair Value, Measurements, Nonrecurring | International Technology
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pre tax impairment charges			$ 80