Fair Value Measurements (Details 7) (USD $) In Millions	3 Months Ended		9 Months Ended																								3 Months Ended	9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011 Fair value on a non-recurring basis Level 2	Dec. 31, 2010 Fair value on a non-recurring basis Level 2	Sep. 30, 2011 Fair value on a non-recurring basis Level 2 Other investments	Dec. 31, 2010 Fair value on a non-recurring basis Level 2 Other investments	Sep. 30, 2011 Fair value on a non-recurring basis Level 3	Dec. 31, 2010 Fair value on a non-recurring basis Level 3	Sep. 30, 2011 Fair value on a non-recurring basis Level 3 Investment real estate	Dec. 31, 2010 Fair value on a non-recurring basis Level 3 Investment real estate	Sep. 30, 2011 Fair value on a non-recurring basis Level 3 Other investments	Dec. 31, 2010 Fair value on a non-recurring basis Level 3 Other investments	Sep. 30, 2011 Fair value on a non-recurring basis Level 3 Aircraft	Dec. 31, 2010 Fair value on a non-recurring basis Level 3 Aircraft	Dec. 31, 2010 Fair value on a non-recurring basis Level 3 Other assets	Sep. 30, 2011 Fair value on a non-recurring basis Total Fair Value	Dec. 31, 2010 Fair value on a non-recurring basis Total Fair Value	Sep. 30, 2011 Fair value on a non-recurring basis Total Fair Value Investment real estate	Dec. 31, 2010 Fair value on a non-recurring basis Total Fair Value Investment real estate	Sep. 30, 2011 Fair value on a non-recurring basis Total Fair Value Other investments	Dec. 31, 2010 Fair value on a non-recurring basis Total Fair Value Other investments	Sep. 30, 2011 Fair value on a non-recurring basis Total Fair Value Aircraft	Dec. 31, 2010 Fair value on a non-recurring basis Total Fair Value Aircraft	Dec. 31, 2010 Fair value on a non-recurring basis Total Fair Value Other assets	Sep. 30, 2010 Investment real estate	Sep. 30, 2011 Investment real estate	Sep. 30, 2010 Investment real estate	Sep. 30, 2011 Other investments	Sep. 30, 2010 Other investments	Sep. 30, 2011 Other investments	Sep. 30, 2010 Other investments	Sep. 30, 2011 Aircraft	Sep. 30, 2010 Aircraft	Sep. 30, 2011 Aircraft	Sep. 30, 2010 Aircraft	Sep. 30, 2010 Other assets
Fair Value, Assets Measured on Non-recurring Basis
Assets at Fair Value, Non-Recurring Basis					$ 194	$ 4	$ 194	$ 4	$ 4,131	$ 8,202	$ 525	$ 1,588	$ 2,105	$ 2,388	$ 1,501	$ 4,224	$ 2	$ 4,325	$ 8,206	$ 525	$ 1,588	$ 2,299	$ 2,392	$ 1,501	$ 4,224	$ 2
Impairment Charges	$ 1,699	$ 515	$ 2,217	$ 1,534																							$ 21	$ 15	$ 551	$ 181	$ 29	$ 526	$ 106	$ 1,518	$ 465	$ 1,676	$ 872	$ 5