CONSOLIDATED BALANCE SHEET (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Receivables, discounts and allowances	$ 1	$ 1
Property and equipment, accumulated depreciation	$ 3,306	$ 3,287
Common shares, par value	$ 1.25	$ 1.25
Common shares, authorized	1,360,000,000	1,360,000,000
Common shares, issued	748,528,131	510,483,285
Common shares, outstanding	748,528,000	510,483,000
6.375 percent Mandatory Convertible Preference Shares, Series A
Preference shares, par value	$ 1.00	$ 1.00
Preference shares, liquidation	$ 50.00	$ 50.00
Preference shares, authorized	40,000,000	40,000,000
Preference shares, issued	0	13,799,711
Preference shares, outstanding	0	13,799,711