Incentive Plans (Changes in Stock Options Outstanding) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Number of Shares
Exercised	(119,994)	[1]	(303,685)	[1]	(482,974)	[1]
Outstanding at end of year	5,602,250
Exercisable at end of year	3,030,105
Stock Options [Member]
Number of Shares
Outstanding at beginning of year	6,006,585		5,907,359		5,434,228
Granted at FMV	772,900		1,320,176		1,870,500
Exercised	(862,407)		(1,335,355)		(823,855)
Forfeited	(314,828)		(228,576)		(573,514)
Murphy USA Inc. spin-off adjustment			615,917
Outstanding at end of year	5,602,250		6,006,585		5,907,359
Exercisable at end of year	3,030,105		2,435,322		2,474,636		2,319,735
Average Exercise Price
Outstanding at beginning of year	$ 56.80		$ 55.17		$ 55.17
Granted stock options, exercise price	$ 55.82		$ 55.26		$ 57.96
Exercised	$ 49.27		$ 45.84		$ 38.37
Forfeited	$ 54.53		$ 58.01		$ 60.43
Surrendered in connection with separation of Murphy USA Inc.			$ 55.99
Murphy USA Inc. spin-off adjustment			$ 52.09
Outstanding at end of year	$ 57.95		$ 56.80		$ 55.17
Exercisable at end of year	$ 53.10		$ 51.79		$ 54.43		$ 51.14
Stock Options [Member] | Spin [Member]
Number of Shares
Surrendered in connection with separation of Murphy USA Inc.			(272,936)

[1] Shares issued upon exercise of stock options and award of restricted stock are less than the amount reflected in Note J due to withholdings for statutory income taxes owed upon issuance of shares.