Condensed Consolidating Financial Statements (Condensed Consolidating Statement Of Cash Flows) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Condensed Consolidating Financial Statements [Line Items]
Net cash provided by operating activities	$ 3,238	$ 2,986	$ 2,855
Cash flows from investing activities:
Business acquisitions, net of cash acquired	(1,560)	(233)	(811)
Capital expenditures	(458)	(370)	(385)
Purchases of held-to-maturity securities	(459)	(468)	(337)
Maturities of held-to-maturity securities	441	605
Purchases of available-for-sale securities	(373)	(226)	(152)
Other, net	435	58	141
Net cash used by investing activities	(1,974)	(408)	(1,392)
Cash flows from financing activities:
Repayments of commercial paper, net			(904)
Proceeds from fixed-rate notes	1,497		747
Purchases of common stock	(1,468)	(1,185)	(209)
Repayment of fixed-rate notes	(750)	(700)
Dividends paid	(673)	(631)	(577)
Proceeds from option exercises	198	277	142
Other, net	193	13	(72)
Net cash used by financing activities	(1,201)	(2,226)	(806)
Net cash used by discontinued operations	(27)	(2)	(15)
Net increase in cash and equivalents	36	350	642
Cash and equivalents at beginning of year	2,613	2,263	1,621
Cash and equivalents at end of year	2,649	2,613	2,263
Parent [Member]
Condensed Consolidating Financial Statements [Line Items]
Net cash provided by operating activities	(359)	(391)	(172)
Cash flows from investing activities:
Business acquisitions, net of cash acquired	(233)		(641)
Capital expenditures	(6)	(10)	(7)
Purchases of held-to-maturity securities	(459)	(237)	(97)
Maturities of held-to-maturity securities	334	273
Purchases of available-for-sale securities	(274)
Other, net	246	(12)	118
Net cash used by investing activities	(392)	14	(627)
Cash flows from financing activities:
Repayments of commercial paper, net			(904)
Proceeds from fixed-rate notes	1,497		747
Purchases of common stock	(1,468)	(1,185)
Repayment of fixed-rate notes	(750)	(700)
Dividends paid	(673)	(631)	(577)
Proceeds from option exercises		277
Other, net	216	18	(67)
Net cash used by financing activities	(1,178)	(2,221)	(801)
Cash sweep/funding by parent	1,851	2,800	2,260
Net increase in cash and equivalents	(78)	202	660
Cash and equivalents at beginning of year	1,608	1,406	746
Cash and equivalents at end of year	1,530	1,608	1,406
Guarantors On A Combined Basis [Member]
Condensed Consolidating Financial Statements [Line Items]
Net cash provided by operating activities	3,524	2,884	2,872
Cash flows from investing activities:
Business acquisitions, net of cash acquired	(1,327)	(163)	(168)
Capital expenditures	(381)	(301)	(297)
Purchases of available-for-sale securities	(99)
Other, net	192	70	21
Net cash used by investing activities	(1,615)	(394)	(444)
Cash flows from financing activities:
Other, net	(20)	(1)	(2)
Net cash used by financing activities	(20)	(1)	(2)
Cash sweep/funding by parent	(1,889)	(2,489)	(2,426)
Other Subsidiaries On A Combined Basis [Member]
Condensed Consolidating Financial Statements [Line Items]
Net cash provided by operating activities	73	493	155
Cash flows from investing activities:
Business acquisitions, net of cash acquired		(70)	(2)
Capital expenditures	(71)	(59)	(81)
Purchases of held-to-maturity securities		(231)	(240)
Maturities of held-to-maturity securities	107	332
Other, net	(3)		2
Net cash used by investing activities	33	(28)	(321)
Cash flows from financing activities:
Other, net	(3)	(4)	(3)
Net cash used by financing activities	(3)	(4)	(3)
Net cash used by discontinued operations	(27)	(2)	(15)
Cash sweep/funding by parent	38	(311)	166
Net increase in cash and equivalents	114	148	(18)
Cash and equivalents at beginning of year	1,005	857	875
Cash and equivalents at end of year	$ 1,119	$ 1,005	$ 857