v2.4.0.6
Long-Term Debt (Summarized Long-Term Debt) (Details) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2011
Dec. 31, 2010
Debt Instrument, Unamortized Premium 421  
Long-term debt 9,322 12,227
SeaRiver Maritime Financial Holdings, Inc. [Member]
   
Long-term debt   2,389
Esso (Thailand) Public Company Ltd. [Member]
   
Debt Instrument, maturity date range, start 2012-12-31 2012-12-31
Debt Instrument, maturity date range, end 2017-12-31 2017-12-31
Guaranteed Debt Securities Due 2011 [Member] | SeaRiver Maritime Financial Holdings, Inc. [Member]
   
Debt maturity   Oct. 01, 2011
Guaranteed Deferred Interest Debentures Due 2012 [Member] | SeaRiver Maritime Financial Holdings, Inc. [Member]
   
Long-term debt   2,389 [1]
Debt maturity Sep. 01, 2012 Sep. 01, 2012 [1]
7.500% Senior Note Due 2012 [Member] | XTO Energy Inc. [Member]
   
Senior notes, noncurrent   199
Interest rate 7.50%  
Debt maturity Apr. 15, 2012  
5.900% Senior Note Due 2012 [Member] | XTO Energy Inc. [Member]
   
Senior notes, noncurrent   233
Interest rate 5.90%  
Debt maturity Aug. 01, 2012  
6.250% Senior Note Due 2013 [Member] | XTO Energy Inc. [Member]
   
Senior notes, noncurrent 185 193
Interest rate 6.25%  
Debt maturity Apr. 15, 2013  
4.625% Senior Note Due 2013 [Member] | XTO Energy Inc. [Member]
   
Senior notes, noncurrent 145 149
Interest rate 4.625%  
Debt maturity Jun. 15, 2013  
5.750% Senior Note Due 2013 [Member] | XTO Energy Inc. [Member]
   
Senior notes, noncurrent 346 359
Interest rate 5.75%  
Debt maturity Dec. 15, 2013  
4.900% Senior Note Due 2014 [Member] | XTO Energy Inc. [Member]
   
Senior notes, noncurrent 260 267
Interest rate 4.90%  
Debt maturity Feb. 01, 2014  
5.000% Senior Note Due 2015 [Member] | XTO Energy Inc. [Member]
   
Senior notes, noncurrent 138 142
Interest rate 5.00%  
Debt maturity Jan. 31, 2015  
5.300% Senior Note Due 2015 [Member] | XTO Energy Inc. [Member]
   
Senior notes, noncurrent 255 262
Interest rate 5.30%  
Debt maturity Jun. 30, 2015  
5.650% Senior Note Due 2016 [Member] | XTO Energy Inc. [Member]
   
Senior notes, noncurrent 222 227
Interest rate 5.65%  
Debt maturity Apr. 01, 2016  
6.250% Senior Note Due 2017 [Member] | XTO Energy Inc. [Member]
   
Senior notes, noncurrent 513 534
Interest rate 6.25%  
Debt maturity Aug. 01, 2017  
5.500% Senior Note Due 2018 [Member] | XTO Energy Inc. [Member]
   
Senior notes, noncurrent 402 420
Interest rate 5.50%  
Debt maturity Jun. 15, 2018  
6.500% Senior Note Due 2018 [Member] | XTO Energy Inc. [Member]
   
Senior notes, noncurrent 506 524
Interest rate 6.50%  
Debt maturity Dec. 15, 2018  
6.100% Senior Note Due 2036 [Member] | XTO Energy Inc. [Member]
   
Senior notes, noncurrent 203 204
Interest rate 6.10%  
Debt maturity Apr. 01, 2036  
6.750% Senior Note Due 2037 [Member] | XTO Energy Inc. [Member]
   
Senior notes, noncurrent 317 329
Interest rate 6.75%  
Debt maturity Aug. 01, 2037  
6.375% Senior Note Due 2038 [Member] | XTO Energy Inc. [Member]
   
Senior notes, noncurrent 241 258
Interest rate 6.375%  
Debt maturity Jun. 15, 2038  
Variable Note Due 2035 [Member] | Mobil Services (Bahamas) Ltd. [Member]
   
Senior notes, noncurrent 972 [2] 972 [2]
Debt maturity May 18, 2035 May 18, 2035
Average effective interest rate 0.20% 0.30%
Variable Note Due 2034 [Member] | Mobil Services (Bahamas) Ltd. [Member]
   
Senior notes, noncurrent 311 [3] 311 [3]
Debt maturity Sep. 15, 2034 Sep. 15, 2034
Average effective interest rate 0.30% 0.40%
Variable Notes Due 2013-2017 [Member] | Mobil Producing Nigeria Unlimited [Member]
   
Senior notes, noncurrent 543 [4] 415 [4]
Debt Instrument, maturity date range, start 2012-12-31 2012-12-31
Debt Instrument, maturity date range, end 2017-12-31 2017-12-31
Average effective interest rate 4.20% 4.60%
Variable Notes Due 2013-2017 [Member] | Esso (Thailand) Public Company Ltd. [Member]
   
Senior notes, noncurrent 413 [5] 522 [5]
Average effective interest rate 3.20% 1.70%
Debentures Due 2021 [Member] | Mobil Corporation [Member]
   
Other long-term debt 248 248
Interest rate 8.625%  
Debt maturity Aug. 15, 2021 Aug. 15, 2021
Industrial Revenue Bonds Due 2012-2051 [Member] | Combined Exxon Mobil And Affiliates [Member]
   
Other long-term debt 2,315 [6] 2,247 [6]
Debt Instrument, maturity date range, start 2012-12-31 2012-12-31
Debt Instrument, maturity date range, end 2051-12-31 2051-12-31
Average effective interest rate 0.10% 0.20%
Other U.S. Dollar Obligations [Member] | Combined Exxon Mobil And Affiliates [Member]
   
Other U.S. dollar obligations 496 [7] 454 [7]
Average effective interest rate 4.80% 4.70%
Other Foreign Currency Obligations [Member] | Combined Exxon Mobil And Affiliates [Member]
   
Other foreign currency obligations 31 65
Capitalized Lease Obligations [Member] | Combined Exxon Mobil And Affiliates [Member]
   
Average effective interest rate 8.50% 8.10%
Long-term debt 260 [8] 304 [8]
[1] Additional information is provided for this subsidiary on the following pages.
[2] Average effective interest rate of 0.2% in 2011 and 0.3% in 2010.
[3] Average effective interest rate of 0.3% in 2011 and 0.4% in 2010.
[4] Average effective interest rate of 4.2% in 2011 and 4.6% in 2010.
[5] Average effective interest rate of 3.2% in 2011 and 1.7% in 2010.
[6] Average effective interest rate of 0.1% in 2011 and 0.2% in 2010.
[7] Average effective interest rate of 4.8% in 2011 and 4.7% in 2010.
[8] Average imputed interest rate of 8.5% in 2011 and 8.1% in 2010.