CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) shares in Thousands, $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Accounts receivable, allowance	$ 164	$ 178
Preferred stock-non-redeemable, par value (in dollars per share)	$ 25.00	$ 25.00
Preferred stock-non-redeemable, authorized shares (shares)	2,000	2,000
Preferred stock-non-redeemable, issued shares (shares)	7	7
Preferred stock-non-redeemable, outstanding shares (shares)	7	7
Common stock, par value (in dollars per share)	$ 1.00	$ 1.00
Common stock, authorized shares (shares)	1,600,000	1,600,000
Common stock, issued shares (shares)	1,069,169	546,545
Common stock, outstanding shares (shares)	1,069,169	546,545