Employee Benefit Plans (Cash Flows) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 28, 2014	Dec. 28, 2012	Dec. 26, 2014
Defined Benefit Plan Disclosure [Line Items]
Employer minimum required contribution		$ 25
Significant expected contributions	0
Pension Benefits [Member]
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2015			207
2016			188
2017			188
2018			185
2019			186
2020-2023			931
Total			1,885
Post-retirement Benefits [Member]
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2015			37
2016			34
2017			33
2018			30
2019			28
2020-2023			114
Total			276
Qualified Employer Contributions [Member] | Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer Contributions		$ 275