Fair Value Measurements (Assets Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Millions	Oct. 27, 2019	Oct. 28, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of fixed income securities	$ 4,093	$ 3,982
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments, fair value	45	38
Assets, fair value disclosure	4,138	4,020
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of fixed income securities	2,000	1,896
Equity investments, fair value	45	38
Assets, fair value disclosure	2,045	1,934
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of fixed income securities	2,093	2,086
Equity investments, fair value	0	0
Assets, fair value disclosure	2,093	2,086
Fair Value, Measurements, Recurring | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of fixed income securities	1,677	1,599
Fair Value, Measurements, Recurring | Money market funds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of fixed income securities	1,677	1,599
Fair Value, Measurements, Recurring | Money market funds | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of fixed income securities	0	0
Fair Value, Measurements, Recurring | U.S. Treasury and agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of fixed income securities	341	333
Fair Value, Measurements, Recurring | U.S. Treasury and agency securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of fixed income securities	323	297
Fair Value, Measurements, Recurring | U.S. Treasury and agency securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of fixed income securities	18	36
Fair Value, Measurements, Recurring | Non-U.S. government securities*
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of fixed income securities	10	10
Fair Value, Measurements, Recurring | Non-U.S. government securities* | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of fixed income securities	0	0
Fair Value, Measurements, Recurring | Non-U.S. government securities* | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of fixed income securities	10	10
Fair Value, Measurements, Recurring | Municipal securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of fixed income securities	406	395
Fair Value, Measurements, Recurring | Municipal securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of fixed income securities	0	0
Fair Value, Measurements, Recurring | Municipal securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of fixed income securities	406	395
Fair Value, Measurements, Recurring | Commercial paper, corporate bonds and medium-term notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of fixed income securities	1,024	1,054
Fair Value, Measurements, Recurring | Commercial paper, corporate bonds and medium-term notes | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of fixed income securities	0	0
Fair Value, Measurements, Recurring | Commercial paper, corporate bonds and medium-term notes | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of fixed income securities	1,024	1,054
Fair Value, Measurements, Recurring | Asset-backed and mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of fixed income securities	635	591
Fair Value, Measurements, Recurring | Asset-backed and mortgage-backed securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of fixed income securities	0	0
Fair Value, Measurements, Recurring | Asset-backed and mortgage-backed securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of fixed income securities	635	591
Fair Value, Measurements, Recurring | Publicly Traded Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments, fair value	45	38
Fair Value, Measurements, Recurring | Publicly Traded Equity Securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments, fair value	45	38
Fair Value, Measurements, Recurring | Publicly Traded Equity Securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments, fair value	$ 0	$ 0