NOTES PAYABLE - Additional Information (Detail)	1 Months Ended	9 Months Ended									1 Months Ended				1 Months Ended			1 Months Ended												1 Months Ended				1 Months Ended
	Jun. 30, 2012	Sep. 30, 2012 JPY (¥)	Feb. 29, 2012 series	Sep. 30, 2012 1.47% yen-denominated Samurai notes due July 2014 JPY (¥)	Dec. 31, 2011 1.47% yen-denominated Samurai notes due July 2014 JPY (¥)	Sep. 30, 2012 1.84% yen-denominated Samurai notes due July 2016 JPY (¥)	Dec. 31, 2011 1.84% yen-denominated Samurai notes due July 2016 JPY (¥)	Sep. 30, 2012 Variable interest rate yen-denominated Samurai notes due July 2014 JPY (¥)	Dec. 31, 2011 Variable interest rate yen-denominated Samurai notes due July 2014 JPY (¥)	Feb. 29, 2012 Senior Notes USD ($)	Jul. 31, 2012 2.65% senior notes due February 2017 USD ($)	Feb. 29, 2012 2.65% senior notes due February 2017 USD ($)	Feb. 29, 2012 2.65% senior notes due February 2017 JPY (¥)	Sep. 30, 2012 2.65% senior notes due February 2017 USD ($)	Feb. 29, 2012 4.00% senior notes due February 2022 USD ($)	Feb. 29, 2012 4.00% senior notes due February 2022 JPY (¥)	Sep. 30, 2012 4.00% senior notes due February 2022 USD ($)	Sep. 30, 2012 5.50% subordinated notes due September 2052 USD ($)	Sep. 30, 2012 5.50% subordinated notes due September 2052 JPY (¥)	Sep. 30, 2012 6.45% senior notes due August 2040 USD ($)	Dec. 31, 2011 6.45% senior notes due August 2040 USD ($)	Sep. 30, 2012 3.45% senior notes due August 2015	Dec. 31, 2011 3.45% senior notes due August 2015	Sep. 30, 2012 6.90% senior notes due December 2039 USD ($)	Dec. 31, 2011 6.90% senior notes due December 2039 USD ($)	Sep. 30, 2012 8.50% senior notes due May 2019	Dec. 31, 2011 8.50% senior notes due May 2019	Sep. 30, 2012 2.26% yen-denominated Uridashi notes due September 2016 JPY (¥)	Dec. 31, 2011 2.26% yen-denominated Uridashi notes due September 2016 JPY (¥)	Jun. 30, 2012 1.87% yen-denominated Samurai notes paid June 2012 USD ($)	Jun. 30, 2012 1.87% yen-denominated Samurai notes paid June 2012 JPY (¥)	Dec. 31, 2011 1.87% yen-denominated Samurai notes paid June 2012 JPY (¥)	Sep. 30, 2012 Notes Payable USD ($)	Oct. 31, 2012 Issuance of Debt Subsequent Event 5.50% subordinated notes due September 2052 USD ($)	Oct. 31, 2012 Issuance of Debt Subsequent Event 5.50% subordinated notes due September 2052 JPY (¥)
Debt Instrument [Line Items]
Debt instrument maturity period											5 years	5 years	5 years		10 years	10 years		40 years	40 years
Samurai notes redeemed upon maturity																														$ 337,000,000	¥ 26,600,000,000
Number of series of senior notes issued through a U.S. public debt offering (in series)			2
Notes payable, principal amount				28,700,000,000	28,700,000,000	15,800,000,000	15,800,000,000	5,500,000,000	5,500,000,000	750,000,000	250,000,000	400,000,000		650,000,000	350,000,000		350,000,000	450,000,000		450,000,000	450,000,000			400,000,000	400,000,000			8,000,000,000	8,000,000,000			26,600,000,000		50,000,000
Debt instrument effective principal amount after cross currency swap													30,900,000,000			27,000,000,000			35,300,000,000																3,900,000,000
Notes payable, interest rate				1.47%	1.47%	1.84%	1.84%	1.34%	1.34%		2.65%	2.65%	2.65%	2.65%	4.00%	4.00%	4.00%	5.50%	5.50%	6.45%	6.45%	3.45%	3.45%	6.90%	6.90%	8.50%	8.50%	2.26%	2.26%			1.87%		5.50%	5.50%
Minimum prinicipal amount outstanding following partial redemption																		25,000,000
Notes payable, effective interest rate								1.475%				1.22%	1.22%	1.22%	2.07%	2.07%	2.07%	4.41%	4.41%															4.42%	4.42%
Line of credit facility term	364 days
Line of credit facility, maximum borrowing capacity		50,000,000,000
Line of credit facility, interest rate description	Borrowings will bear interest at LIBOR plus the applicable margin of 1.025%.
Line of credit facility, commitment fee percentage		0.10%
Line of credit facility, amount outstanding		0
Extended line of credit facility term	364 days
Notes payable, debt default, amount																																	$ 0
Derivative instrument maturity period																		5 years	5 years															5 years	5 years