Debt (Narrative) (Details) - USD ($) $ in Millions | Sep. 06, 2016 | Mar. 01, 2016 | Feb. 12, 2016 | Sep. 15, 2015 | May 28, 2015 | Jan. 29, 2017 | Jan. 31, 2016 | Feb. 01, 2015 |
Debt Instrument [Line Items] | | | | | | | | |
Redemption Price of Long-Term Debt | | | | | | 100.00% | | |
Change of Control Redemption Price of Long-Term Debt | | | | | | 101.00% | | |
Interest Costs Incurred [Abstract] | | | | | | | | |
Interest Capitalized | | | | | | $ 1 | $ 2 | $ 2 |
Maturities of Long-Term Debt [Abstract] | | | | | | | | |
Maturities of Long-Term Debt for 2017 | | | | | | 542 | | |
Maturities of Long-Term Debt for 2018 | | | | | | 1,200 | | |
Maturities of Long-Term Debt for 2019 | | | | | | 1,000 | | |
Maturities of Long-Term Debt for 2020 | | | | | | 573 | | |
Maturities of Long-Term Debt for 2021 | | | | | | 2,400 | | |
Maturities of Long-Term Debt for fiscal years thereafter | | | | | | $ 17,200 | | |
2.125% Senior Notes Due September 15, 2026 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Face Amount of Long-Term Debt | $ 1,000 | | | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | 2.125% | | | | | 2.125% | | |
Maturity Date of Long-Term Debt | Sep. 15, 2026 | | | | | | | |
Unamortized Discount of Long-Term Debt | $ 11 | | | | | | | |
Frequency of Periodic Payment of Long-Term Debt | semi-annually on March 15 and September 15 | | | | | | | |
3.5% Senior Notes Due September 15, 2056 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Face Amount of Long-Term Debt | $ 1,000 | | | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | 3.50% | | | | | 3.50% | | |
Maturity Date of Long-Term Debt | Sep. 15, 2056 | | | | | | | |
Unamortized Discount of Long-Term Debt | $ 19 | | | | | | | |
Frequency of Periodic Payment of Long-Term Debt | semi-annually on March 15 and September 15 | | | | | | | |
2.00% Senior Notes Due April 1, 2021 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Face Amount of Long-Term Debt | | | $ 1,350 | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | 2.00% | | | 2.00% | | |
Maturity Date of Long-Term Debt | | | Apr. 1, 2021 | | | | | |
Unamortized Discount of Long-Term Debt | | | $ 5 | | | | | |
Frequency of Periodic Payment of Long-Term Debt | | | semi-annually on April 1 and October 1 | | | | | |
3.00% Senior Notes Due April 1, 2026 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Face Amount of Long-Term Debt | | | $ 1,300 | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | 3.00% | | | 3.00% | | |
Maturity Date of Long-Term Debt | | | Apr. 1, 2026 | | | | | |
Unamortized Discount of Long-Term Debt | | | $ 8 | | | | | |
Frequency of Periodic Payment of Long-Term Debt | | | semi-annually on April 1 and October 1 | | | | | |
Additional 4.25 Senior Notes Due April 1, 2046 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Face Amount of Long-Term Debt | | | $ 350 | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | 4.25% | | | | | |
Maturity Date of Long-Term Debt | | | Apr. 1, 2046 | | | | | |
Debt Instrument, Unamortized Premium | | | $ 2 | | | | | |
Frequency of Periodic Payment of Long-Term Debt | | | semi-annually on April 1 and October 1 | | | | | |
4.25% Senior Notes Due April 1, 2046 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Face Amount of Long-Term Debt | | | $ 1,600 | | $ 1,250 | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | | | 4.25% | 4.25% | | |
Maturity Date of Long-Term Debt | | | | | Apr. 1, 2046 | | | |
Unamortized Discount of Long-Term Debt | | | | | $ 3 | | | |
Frequency of Periodic Payment of Long-Term Debt | | | | | semi-annually on April 1 and October 1 | | | |
5.40% Senior Notes Due March 1, 2016 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | | 5.40% | | | | | | |
Maturity Date of Long-Term Debt | | Mar. 1, 2016 | | | | | | |
Floating Rate Senior Notes Due September 15, 2017 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Face Amount of Long-Term Debt | | | | $ 500 | | | | |
Maturity Date of Long-Term Debt | | | | Sep. 15, 2017 | | | | |
Frequency of Periodic Payment of Long-Term Debt | | | | quarterly on March 15, June 15, September 15 and December 15 | | | | |
3.35% Senior Notes Due September 15, 2025 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Face Amount of Long-Term Debt | | | | $ 1,000 | | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | | 3.35% | | 3.35% | | |
Maturity Date of Long-Term Debt | | | | Sep. 15, 2025 | | | | |
Unamortized Discount of Long-Term Debt | | | | $ 1 | | | | |
Frequency of Periodic Payment of Long-Term Debt | | | | semi-annually on March 15 and September 15 | | | | |
2.625% Senior Notes Due June 1, 2022 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Face Amount of Long-Term Debt | | | | | $ 1,250 | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | | | 2.625% | 2.625% | | |
Maturity Date of Long-Term Debt | | | | | Jun. 1, 2022 | | | |
Unamortized Discount of Long-Term Debt | | | | | $ 5 | | | |
Frequency of Periodic Payment of Long-Term Debt | | | | | semi-annually on June 1 and December 1 | | | |
2.25% Senior Notes Due September 10, 2018 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | | | | 2.25% | | |
Maturity Date of Long-Term Debt | | | | | | Sep. 10, 2018 | | |
Frequency of Periodic Payment of Long-Term Debt | | | | | | semi-annually on March 10 and September 10 | | |
2.00% Senior Notes Due June 15, 2019 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | | | | 2.00% | | |
Maturity Date of Long-Term Debt | | | | | | Jun. 15, 2019 | | |
Frequency of Periodic Payment of Long-Term Debt | | | | | | semi-annually on June 15 and December 15 | | |
3.95% Senior Notes Due September 15, 2020 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | | | | 3.95% | | |
Maturity Date of Long-Term Debt | | | | | | Sep. 15, 2020 | | |
Frequency of Periodic Payment of Long-Term Debt | | | | | | semi-annually on March 15 and September 15 | | |
4.40% Senior Notes Due April 1, 2021 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | | | | 4.40% | | |
Maturity Date of Long-Term Debt | | | | | | Apr. 1, 2021 | | |
Frequency of Periodic Payment of Long-Term Debt | | | | | | semi-annually on April 1 and October 1 | | |
2.70% Senior Notes Due April 1, 2023 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | | | | 2.70% | | |
Maturity Date of Long-Term Debt | | | | | | Apr. 1, 2023 | | |
Frequency of Periodic Payment of Long-Term Debt | | | | | | semi-annually on April 1 and October 1 | | |
3.75% Senior Notes Due February 15, 2024 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | | | | 3.75% | | |
Maturity Date of Long-Term Debt | | | | | | Feb. 15, 2024 | | |
Frequency of Periodic Payment of Long-Term Debt | | | | | | semi-annually on February 15 and August 15 | | |
5.875% Senior Notes Due December 16, 2036 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | | | | 5.875% | | |
Maturity Date of Long-Term Debt | | | | | | Dec. 16, 2036 | | |
Frequency of Periodic Payment of Long-Term Debt | | | | | | semi-annually on June 16 and December 16 | | |
5.40% Senior Notes Due September 15, 2040 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | | | | 5.40% | | |
Maturity Date of Long-Term Debt | | | | | | Sep. 15, 2040 | | |
Frequency of Periodic Payment of Long-Term Debt | | | | | | semi-annually on March 15 and September 15 | | |
5.95% Senior Notes Due April 1, 2041 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | | | | 5.95% | | |
Maturity Date of Long-Term Debt | | | | | | Apr. 1, 2041 | | |
Frequency of Periodic Payment of Long-Term Debt | | | | | | semi-annually on April 1 and October 1 | | |
4.20% Senior Notes Due April 1, 2043 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | | | | 4.20% | | |
Maturity Date of Long-Term Debt | | | | | | Apr. 1, 2043 | | |
Frequency of Periodic Payment of Long-Term Debt | | | | | | semi-annually on April 1 and October 1 | | |
4.875% Senior Notes Due February 15, 2044 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | | | | 4.875% | | |
Maturity Date of Long-Term Debt | | | | | | Feb. 15, 2044 | | |
Frequency of Periodic Payment of Long-Term Debt | | | | | | semi-annually on February 15 and August 15 | | |
4.40% Senior Notes Due March 15, 2045 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | | | | 4.40% | | |
Maturity Date of Long-Term Debt | | | | | | Mar. 15, 2045 | | |
Frequency of Periodic Payment of Long-Term Debt | | | | | | semi-annually on March 15 and September 15 | | |
September 2016 Issuance [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Unamortized Discount of Long-Term Debt | $ 30 | | | | | | | |
Debt Issuance Costs, Gross | $ 16 | | | | | | | |
February 2016 Issuance [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Debt Instrument, Unamortized Premium | | | 2 | | | | | |
Unamortized Discount of Long-Term Debt | | | 13 | | | | | |
Debt Issuance Costs, Gross | | | $ 17 | | | | | |
September 2015 Issuance [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Debt Issuance Costs, Gross | | | | $ 7 | | | | |
May 2015 Issuance [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Unamortized Discount of Long-Term Debt | | | | | $ 8 | | | |
Debt Issuance Costs, Gross | | | | | $ 19 | | | |