Restructuring Charges Schedule of Resctucturing Charges Table (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Restructuring Cost and Reserve [Line Items]
Total expected restructuring charges		$ 389
Restructuring charges		203	$ 0
General and Administrative Expense [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges		203
Cash Severance [Member]
Restructuring Cost and Reserve [Line Items]
Total expected restructuring charges		154
Cash Severance [Member] | General and Administrative Expense [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges		131
Retirement Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Total expected restructuring charges	[1]	203
Settlements		0
Retirement Benefits [Member] | General and Administrative Expense [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges	[1]	49
Share-based Compensation [Member]
Restructuring Cost and Reserve [Line Items]
Total expected restructuring charges		32
Share-based Compensation [Member] | General and Administrative Expense [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges		23
Amount to be Recognized in 2017 [Member] | Retirement Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Total expected restructuring charges		$ 10

[1] Includes termination benefits, curtailments, and settlements. There were no settlements recognized during the three months ended March 31, 2016. See Note 13—Pension Plans and Other Postretirement Benefits.