Fair Value Measurements (Fair Value Of Assets And Liabilities) (Details) (USD $) In Millions, unless otherwise specified	Mar. 30, 2013	Dec. 31, 2012
Assets:
Available-for-sale securities, fair value	$ 148	$ 144
U.S. Government, Agency and Government-sponsored Enterprise Obligations [Member]
Assets:
Available-for-sale securities, fair value	18	15
Corporate Bonds [Member]
Assets:
Available-for-sale securities, fair value	7	11
Mortgage-backed Securities [Member]
Assets:
Available-for-sale securities, fair value	2	2
Common Stock and Equivalents [Member]
Assets:
Available-for-sale securities, fair value	11	10
Level 1 [Member]
Liabilities:
Foreign exchange derivative contracts	0	0
Interest agreement derivative contracts	0	0
Level 2 [Member]
Liabilities:
Foreign exchange derivative contracts	4	3
Interest agreement derivative contracts	4	4
Estimate of Fair Value, Fair Value Disclosure [Member]
Liabilities:
Foreign exchange derivative contracts	4	3
Interest agreement derivative contracts	4	4
Sigma Fund Securities [Member] | Level 1 [Member] | U.S. Government, Agency and Government-sponsored Enterprise Obligations [Member]
Assets:
Sigma Fund securities, fair value	0	0
Sigma Fund Securities [Member] | Level 2 [Member] | U.S. Government, Agency and Government-sponsored Enterprise Obligations [Member]
Assets:
Sigma Fund securities, fair value	2,245	1,984
Sigma Fund Securities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. Government, Agency and Government-sponsored Enterprise Obligations [Member]
Assets:
Sigma Fund securities, fair value	2,245	1,984
Foreign Exchange Derivative Contracts [Member] | Level 1 [Member] | Foreign Exchange Derivative Contracts [Member]
Assets:
Foreign exchange derivative contracts, fair value	0	0
Foreign Exchange Derivative Contracts [Member] | Level 2 [Member] | Foreign Exchange Derivative Contracts [Member]
Assets:
Foreign exchange derivative contracts, fair value	2	3
Foreign Exchange Derivative Contracts [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Foreign Exchange Derivative Contracts [Member]
Assets:
Foreign exchange derivative contracts, fair value	2	3
Available-For-Sale Securities [Member] | Level 1 [Member] | U.S. Government, Agency and Government-sponsored Enterprise Obligations [Member]
Assets:
Available-for-sale securities, fair value	0	0
Available-For-Sale Securities [Member] | Level 1 [Member] | Corporate Bonds [Member]
Assets:
Available-for-sale securities, fair value	0	0
Available-For-Sale Securities [Member] | Level 1 [Member] | Mortgage-backed Securities [Member]
Assets:
Available-for-sale securities, fair value	0	0
Available-For-Sale Securities [Member] | Level 1 [Member] | Common Stock and Equivalents [Member]
Assets:
Available-for-sale securities, fair value	3	3
Available-For-Sale Securities [Member] | Level 2 [Member] | U.S. Government, Agency and Government-sponsored Enterprise Obligations [Member]
Assets:
Available-for-sale securities, fair value	18	15
Available-For-Sale Securities [Member] | Level 2 [Member] | Corporate Bonds [Member]
Assets:
Available-for-sale securities, fair value	7	11
Available-For-Sale Securities [Member] | Level 2 [Member] | Mortgage-backed Securities [Member]
Assets:
Available-for-sale securities, fair value	2	2
Available-For-Sale Securities [Member] | Level 2 [Member] | Common Stock and Equivalents [Member]
Assets:
Available-for-sale securities, fair value	8	7
Available-For-Sale Securities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. Government, Agency and Government-sponsored Enterprise Obligations [Member]
Assets:
Available-for-sale securities, fair value	18	15
Available-For-Sale Securities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Corporate Bonds [Member]
Assets:
Available-for-sale securities, fair value	7	11
Available-For-Sale Securities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Mortgage-backed Securities [Member]
Assets:
Available-for-sale securities, fair value	2	2
Available-For-Sale Securities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Common Stock and Equivalents [Member]
Assets:
Available-for-sale securities, fair value	$ 11	$ 10