Condensed Consolidating Financial Information (Balance Sheet) (Details) - USD ($) $ in Millions		Dec. 31, 2015	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012
Assets
Cash and cash equivalents		$ 3,074	$ 5,207		$ 5,400	$ 3,474
Accounts and notes receivable		5,173	7,255
Inventories		3,477	3,397
Prepaid expenses and other current assets	[1]	532	833	[2]
Total Current Assets		12,256	16,692
Investments and long-term receivables		12,143	10,189
Net properties, plants and equipment		19,721	17,346
Goodwill		3,275	3,274		3,096
Intangibles		906	900
Other assets	[1]	279	291	[2]
Total Assets		48,580	48,692		49,769
Liabilities and Equity
Accounts payable		5,655	8,064
Short-term debt		44	842
Accrued income and other taxes		878	878
Employee benefit obligations		576	462
Other accruals		378	848
Total Current Liabilities		7,531	11,094
Long-term debt	[1]	8,843	7,793	[2]
Asset retirement obligations and accrued environmental costs		665	683
Deferred income taxes		6,041	5,491
Employee benefit obligations		1,285	1,305
Other liabilities and deferred credits		277	289
Total Liabilities		24,642	26,655
Common stock		11,405	12,812
Retained earnings		12,348	9,309
Accumulated other comprehensive income (loss)		(653)	(531)		37	(314)
Noncontrolling interests		838	447
Total Liabilities and Equity		48,580	48,692
Consolidating Adjustments [Member]
Assets
Accounts and notes receivable		(701)	(1,102)
Total Current Assets		(701)	(1,102)
Investments and long-term receivables		(52,635)	(43,479)
Other assets		(4)	(4)	[2]
Total Assets		(53,340)	(44,585)
Liabilities and Equity
Accounts payable		(701)	(1,102)
Total Current Liabilities		(701)	(1,102)
Deferred income taxes		(4)	(4)
Other liabilities and deferred credits		(8,968)	(4,041)
Total Liabilities		(9,673)	(5,147)
Common stock		(36,092)	(33,645)
Retained earnings		(8,347)	(6,317)
Accumulated other comprehensive income (loss)		772	524
Total Liabilities and Equity		(53,340)	(44,585)
Phillips 66 [Member]
Assets
Accounts and notes receivable		14	14
Prepaid expenses and other current assets		2	5	[2]
Total Current Assets		16	19
Investments and long-term receivables		33,315	30,141
Other assets		16	16	[2]
Total Assets		33,347	30,176
Liabilities and Equity
Short-term debt			798
Other accruals		59	65
Total Current Liabilities		59	863
Long-term debt		7,413	7,409	[2]
Other liabilities and deferred credits		2,746	285
Total Liabilities		10,218	8,557
Common stock		11,405	12,812
Retained earnings		12,377	9,338
Accumulated other comprehensive income (loss)		(653)	(531)
Total Liabilities and Equity		33,347	30,176
Phillips 66 Company [Member]
Assets
Cash and cash equivalents		575	2,045		2,162	2,410
Accounts and notes receivable		3,643	5,069
Inventories		2,171	2,026
Prepaid expenses and other current assets		382	429	[2]
Total Current Assets		6,771	9,569
Investments and long-term receivables		24,068	18,896
Net properties, plants and equipment		12,651	12,267
Goodwill		3,040	3,040
Intangibles		726	694
Other assets		154	159	[2]
Total Assets		47,410	44,625
Liabilities and Equity
Accounts payable		4,015	5,618
Short-term debt		25	26
Accrued income and other taxes		320	356
Employee benefit obligations		528	409
Other accruals		240	242
Total Current Liabilities		5,128	6,651
Long-term debt		158	159	[2]
Asset retirement obligations and accrued environmental costs		496	494
Deferred income taxes		4,500	4,240
Employee benefit obligations		1,094	1,074
Other liabilities and deferred credits		2,765	1,919
Total Liabilities		14,141	14,537
Common stock		25,404	25,405
Retained earnings		8,518	5,214
Accumulated other comprehensive income (loss)		(653)	(531)
Total Liabilities and Equity		47,410	44,625
All Other Subsidiaries [Member]
Assets
Cash and cash equivalents		2,499	3,162		$ 3,238	$ 1,064
Accounts and notes receivable		2,217	3,274
Inventories		1,306	1,371
Prepaid expenses and other current assets		148	399	[2]
Total Current Assets		6,170	8,206
Investments and long-term receivables		7,395	4,631
Net properties, plants and equipment		7,070	5,079
Goodwill		235	234
Intangibles		180	206
Other assets		113	120	[2]
Total Assets		21,163	18,476
Liabilities and Equity
Accounts payable		2,341	3,548
Short-term debt		19	18
Accrued income and other taxes		558	522
Employee benefit obligations		48	53
Other accruals		79	541
Total Current Liabilities		3,045	4,682
Long-term debt		1,272	225	[2]
Asset retirement obligations and accrued environmental costs		169	189
Deferred income taxes		1,545	1,255
Employee benefit obligations		191	231
Other liabilities and deferred credits		3,734	2,126
Total Liabilities		9,956	8,708
Common stock		10,688	8,240
Retained earnings		(200)	1,074
Accumulated other comprehensive income (loss)		(119)	7
Noncontrolling interests		838	447
Total Liabilities and Equity		$ 21,163	$ 18,476

[1] Prior period amounts have been retrospectively adjusted for Accounting Standards Update No. 2015-03.

[2] Prior period amounts have been retrospectively adjusted for Accounting Standards Update No. 2015-03.