CONSOLIDATED BALANCE SHEETS (UNAUDITED) (Parenthetical) - USD ($) shares in Thousands, $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Accounts receivable, allowance	$ 67	$ 67
Accumulated depreciation	$ 21,725	$ 21,318
Preferred stock-non-redeemable, par value (in dollars per share)	$ 25.00	$ 25.00
Preferred stock-non-redeemable, shares authorized (in shares)	2,000	2,000
Preferred stock-non-redeemable, shares issued (in shares)	7	7
Preferred stock-non-redeemable, shares outstanding (in shares)	7	7
Common stock, par value (in dollars per share)	$ 1.00	$ 1.00
Common stock, shares authorized (in shares)	2,200,000	2,200,000
Common stock, shares issued (in shares)	1,015,967	1,008,486
Common stock, shares outstanding (in shares)	1,015,967	1,008,486