SCHEDULE I - PARENT COMPANY FINANCIAL INFORMATION (Condensed Balance Sheets) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 3,394	$ 4,673
Investment securities	13,192	12,554
Other current assets	6,493	5,276
Total current assets	24,893	23,641
Property and equipment, net	3,073	2,371
Equity method investments	141	1,170
Long-term investment securities	780	1,212
Other long-term assets	4,379	2,128
Total assets	44,358	34,969
Current liabilities:
Book overdraft	326	320
Short-term debt	1,953	600
Total current liabilities	15,331	13,394
Long-term debt	10,541	6,060
Other long-term liabilities	2,383	1,787
Total liabilities	28,255	21,241
Commitments and contingencies (Note 17)
Stockholders’ equity:
Preferred stock, $1 par; 10,000,000 shares authorized; none issued	0	0
Common stock, $0.16 2/3 par; 300,000,000 shares authorized; 198,648,742 shares issued at December 31, 2021 and December 31, 2020	33	33
Capital in excess of par value	3,082	2,705
Retained earnings	23,086	20,517
Accumulated other comprehensive income	42	391
Treasury stock, at cost, 69,846,758 shares at December 31, 2021 and 69,787,914 shares at December 31, 2020	(10,163)	(9,918)
Total liabilities and stockholders’ equity	44,358	34,969
Parent Company
Current assets:
Cash and cash equivalents	906	436
Investment securities	428	336
Receivable from operating subsidiaries	1,316	1,187
Other current assets	545	763
Total current assets	3,195	2,722
Property and equipment, net	2,223	1,774
Investments in subsidiaries	26,885	17,005
Equity method investments	52	1,147
Long-term investment securities	207	836
Other long-term assets	407	686
Total assets	32,969	24,170
Current liabilities:
Payable to operating subsidiaries	2,056	1,342
Current portion of notes payable to operating subsidiaries	36	36
Book overdraft	68	120
Short-term debt	1,953	600
Other current liabilities	1,460	1,438
Total current liabilities	5,573	3,536
Long-term debt	10,541	6,060
Other long-term liabilities	775	846
Total liabilities	16,889	10,442
Commitments and contingencies (Note 17)
Stockholders’ equity:
Preferred stock, $1 par; 10,000,000 shares authorized; none issued	0	0
Common stock, $0.16 2/3 par; 300,000,000 shares authorized; 198,648,742 shares issued at December 31, 2021 and December 31, 2020	33	33
Capital in excess of par value	3,082	2,705
Retained earnings	23,086	20,517
Accumulated other comprehensive income	42	391
Treasury stock, at cost, 69,846,758 shares at December 31, 2021 and 69,787,914 shares at December 31, 2020	(10,163)	(9,918)
Total stockholders’ equity	16,080	13,728
Total liabilities and stockholders’ equity	$ 32,969	$ 24,170