Long-Term Debt and Credit Facilities (Narrative) (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended		12 Months Ended				1 Months Ended		1 Months Ended		1 Months Ended					1 Months Ended			1 Months Ended
	Aug. 31, 2012	Sep. 30, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Jul. 15, 2011	Mar. 31, 2013 Senior Unsecured Notes 1.30% due 2018 [Member]	Dec. 31, 2013 Senior Unsecured Notes 1.30% due 2018 [Member]	Mar. 31, 2013 Senior Unsecured Notes 4.10% due 2043 [Member]	Dec. 31, 2013 Senior Unsecured Notes 4.10% due 2043 [Member]	Aug. 31, 2012 Senior Unsecured Revolving Credit Facility Due 2017 [Member]	Mar. 31, 2013 Senior Unsecured Revolving Credit Facility Due 2013 [Member]	Aug. 31, 2012 Senior Unsecured Revolving Credit Facility Due 2013 [Member]	Aug. 31, 2012 Maximum Borrowing Capacity, Multicurrency Sublimit [Member]	Aug. 31, 2012 Maximum Borrowing Capacity, Letter of Credit Sublimit [Member]	Sep. 30, 2011 Senior Unsecured Notes 2.00% due 2016 [Member]	Dec. 31, 2013 Senior Unsecured Notes 2.00% due 2016 [Member]	Dec. 31, 2011 Senior Unsecured Notes 2.00% due 2016 [Member]	Jul. 31, 2011 Maximum [Member]	Jul. 15, 2011 Minimum [Member]
Proceeds from Unsecured Notes Payable							$ 600		$ 400							$ 750
Debt Instrument, Interest Rate, Stated Percentage							1.30%	1.30%	4.10%	4.10%							2.00%	2.00%
Debt Instrument, Unamortized Discount					1		3		6
Line of Credit Facility, Initiation Date	Aug. 22, 2012
Credit facility											1,000		1,000	500	100
Expiration date											Aug. 22, 2017	Apr. 01, 2043	Aug. 05, 2013
Line of Credit Facility, Additional Borrowing Capacity	500
Line of Credit Facility, Commitment Fee Description	5 to 22.5
Line of Credit Facility, Interest Rate Description	bears interest at LIBOR, as defined in the 2012 Facility agreement, plus an applicable margin ranging from 57.5 to 127.5 basis points
Debt Instrument, Maturity Date																Sep. 30, 2016
Proceeds from issuance of long-term debt, net		749	991	0	749
Commercial Paper						500
Debt Instrument, Maturity Date Range, End																			397 days
Debt Instrument, Face Amount																				0.25
Additional borrowing capacity available under all of its existing credit facilities			1,052
Long-term debt, weighted-average interest rate			2.90%
Issuance of long-term debt, unamortized debt issuance costs			16
Debt Instrument, Fair Value Disclosure			2,790	1,866
Interest Expense, Debt			83	63	56
Interest Expense, Long-term Debt			$ 88	$ 55	$ 39