Borrowings (Carrying Value And Fair Value Of Long-Term Borrowings) (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Debt [Line Items]
Maturity Amount	$ 6,200
Unamortized Discount	(14)
Carrying Value	6,186	4,690
Fair Value	6,767
2.25% Notes Due 2012 [Member]
Debt [Line Items]
Maturity Amount	500
Carrying Value	500
Fair Value	501
Floating Rate Notes Due 2013 [Member]
Debt [Line Items]
Maturity Amount	750
Carrying Value	750
Fair Value	745
3.50% Notes Due 2014 [Member]
Debt [Line Items]
Maturity Amount	1,000
Carrying Value	1,000
Fair Value	1,063
1.375% Notes Due 2015 [Member]
Debt [Line Items]
Maturity Amount	750
Unamortized Discount	(1)
Carrying Value	749
Fair Value	764
6.25% Notes Due 2017 [Member]
Debt [Line Items]
Maturity Amount	700
Unamortized Discount	(3)
Carrying Value	697
Fair Value	865
5.00% Notes Due 2019 [Member]
Debt [Line Items]
Maturity Amount	1,000
Unamortized Discount	(2)
Carrying Value	998
Fair Value	1,182
4.25% Notes Due 2021 [Member]
Debt [Line Items]
Maturity Amount	750
Unamortized Discount	(4)
Carrying Value	746
Fair Value	847
3.375% Notes Due 2022 [Member]
Debt [Line Items]
Maturity Amount	750
Unamortized Discount	(4)
Carrying Value	746
Fair Value	$ 800