Earnings per Share (Summary of Earnings Per Share Calculation) (Details) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Earnings Per Share, Basic and Diluted [Abstract]
Income from continuing operations attributable to Phillips 66	$ 3,665		$ 4,076		$ 4,732
Income allocated to participating securities	(5)		(2)
Income from continuing operations available to common stockholders, Basic	3,660		4,074		4,732
Income from continuing operations available to common stockholders, Diluted	3,665		4,076		4,732
Discontinued operations	61		48		43
Net Income available to common stockholders, Basic	3,721		4,122		4,775
Net Income available to common stockholders, Diluted	$ 3,726		$ 4,124		$ 4,775
Weighted-average commons shares outstanding - basic	612,918	[1],[2]	628,835	[1],[2]	627,628	[1],[2]
Dilutive effect of stock-based compensation	6,071		7,929		7,017
Weighted-average commons shares outstanding - diluted	618,989	[1]	636,764	[1]	634,645	[1]
Income from continuing operations attributable to Phillips 66, Per Basic Share	$ 5.97	[1]	$ 6.47	[1]	$ 7.54	[1]
Income from continuing operations attributable to Phillips 66, Per Diluted Share	$ 5.92	[1]	$ 6.40	[1]	$ 7.45	[1]
Discontinued operations, Per Basic Share	$ 0.10	[1]	$ 0.08	[1]	$ 0.07	[1]
Discontinued operations, Per Diluted Share	$ 0.10	[1]	$ 0.08	[1]	$ 0.07	[1]
Earnings per share - basic	$ 6.07	[1]	$ 6.55	[1]	$ 7.61	[1]
Earnings per share - diluted	$ 6.02	[1]	$ 6.48	[1]	$ 7.52	[1]

[1] See Note 11—Earnings Per Share.

[2] Net of provision for income taxes on discontinued operations: $34 million, $27 million, $22 million