Schedule I - Parent Company Financial Information (Condensed Balance Sheets) (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Current assets:
Cash and cash equivalents	$ 1,138	$ 1,306	$ 1,377	$ 1,673
Investment securities	8,090	8,001
Other current assets	2,122	1,670
Total current assets	12,300	11,710
Property and equipment, net	1,218	1,098
Other long-term assets	1,774	1,685
Total assets	20,735	19,979
Current liabilities:
Book overdraft	403	324
Total current liabilities	6,323	6,375
Long-term debt	2,600	2,611
Other long-term liabilities	289	288
Total liabilities	11,419	11,132
Commitments and contingencies
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; 196,275,506 shares issued in 2013 and 194,470,820 shares issued in 2012	33	32
Capital in excess of par value	2,267	2,101
Retained earnings	8,942	7,881
Accumulated other comprehensive income	158	386
Treasury stock, at cost, 42,245,097 shares in 2013 and 36,138,955 shares in 2012	(2,084)	(1,553)
Total stockholders' equity	9,316	8,847	8,063	6,924
Total liabilities and stockholders' equity	20,735	19,979
Parent Company
Current assets:
Cash and cash equivalents	161	151	187	314
Investment securities	347	195
Receivable from operating subsidiaries	777	523
Other current assets	186	97
Total current assets	1,471	966
Property and equipment, net	709	660
Investments in subsidiaries	12,959	12,136
Other long-term assets	82	69
Total assets	15,221	13,831
Current liabilities:
Payable to operating subsidiaries	2,570	1,713
Current portion of notes payable to operating subsidiaries	28	28
Book overdraft	59	52
Other current liabilities	452	376
Total current liabilities	3,109	2,169
Long-term debt	2,600	2,611
Notes payable to operating subsidiaries	9	9
Other long-term liabilities	187	195
Total liabilities	5,905	4,984
Commitments and contingencies
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; 196,275,506 shares issued in 2013 and 194,470,820 shares issued in 2012	33	32
Capital in excess of par value	2,267	2,101
Retained earnings	8,942	7,881
Accumulated other comprehensive income	158	386
Treasury stock, at cost, 42,245,097 shares in 2013 and 36,138,955 shares in 2012	(2,084)	(1,553)
Total stockholders' equity	9,316	8,847
Total liabilities and stockholders' equity	$ 15,221	$ 13,831